JPH0466277B2 - - Google Patents

Description

[Detailed description of the invention]

Technical Field The present invention relates to a novel liquid crystal compound, a liquid crystal composition containing the same, and a liquid crystal element using the liquid crystal composition. BACKGROUND ART Conventional liquid crystal elements include, for example, M. Schadt and W. Helfrich.
Helfrich), “Applied Physics Letters”, Volume 18, No. 4 (“Applied Physics Letters”,
Vol. 18, No. 4) (February 15, 1971), P. 127-128, “Voltage-dependent optical behavior of twisted nematic liquid crystals”
−Dependent Optical Activity of a Twisted
Nematic Liquid Crystal”)
(Twisted nematic) One that uses liquid crystal is known. However, this TN liquid crystal has the problem of generating crosstalk during time-division driving using a matrix electrode structure with high pixel density, which limits the number of pixels. Furthermore, its use as a display has been limited due to its slow electric field response and poor viewing angle characteristics. Furthermore, a display element is known in which a switching element using a thin film transistor is connected to each pixel and switching is performed for each pixel, but the process of forming the thin film transistor on the substrate is extremely complicated, and it is difficult to use a display element with a large area. There are some problems that make it difficult to create. In order to improve the drawbacks of conventional liquid crystal devices, the use of bistable liquid crystal devices was proposed by Clark and Lagerwall (Japanese Patent Laid-Open No. 1983-1973).
-107216, US Pat. No. 4,367,924, etc.). In general, liquid crystals with bistability include:
A ferroelectric liquid crystal having a chiral smectic C phase (SmC ^* ) or H phase (SmH ^* ) is used. Because this ferroelectric liquid crystal has spontaneous polarization, it has an extremely fast response speed, can develop a bistable state with memory properties, and has excellent viewing angle characteristics, so it can be used for large-capacity, large-screen displays. It is suitable as OBJECT OF THE INVENTION The present invention has been made in view of the above points.
An object of the present invention is to provide a liquid crystal composition containing a liquid crystal compound useful for controlling a liquid crystal state, and a liquid crystal element using the liquid crystal composition. Summary of the invention That is, the present invention is based on the general formula () (However, R represents an alkyl group having 1 to 8 carbon atoms, and C ^* represents an optically active asymmetric carbon atom. R ¹ represents an alkyl group or an alkoxy group having 3 to 10 carbon atoms,

【ceremony,

[Expression] If Kuha

[Formula] is shown. x represents 0 or 1, and y represents 1-5. The present invention provides a liquid crystal composition containing at least one compound represented by the following formula and a liquid crystal element using the liquid crystal composition. DETAILED DESCRIPTION OF THE INVENTION A method for producing the liquid crystalline compound of formula () according to the present invention will be described. First, as a starting material, the following general formula () (Here, R represents an alkyl group having 1 to 18 carbon atoms, C ^* represents an asymmetric carbon atom, x is 0 or 1,
y represents 1 to 8. ) is used. The optically active alcohol represented by this formula () has the general formula () (Here, R ₀ is a lower alkyl group, C ^* is an asymmetric carbon atom, x and z are 0 or 1, and x is 0
When x is 1, z is 0 or 1, and when x is 1, z is 0
It is. ), specifically 2-hydroxypropionic acid alkyl ester, 3-hydroxybutyric acid alkyl ester and 3-hydroxy-2
- From methyl propionic acid alkyl ester, according to the following reaction schemes (1) and (2) or the process scheme
It can be easily synthesized by repeating (2).

[Table] RI in the above reaction formula can be selected from a wide range of carbon numbers, specifically iodobutane, iodopentane, iodohexane, iodoheptane, iodooctane, iodononane, iododecane, iodoundecane. , iodododecane, iodotridecane, iodotetradecane, iodopentadecane, iodohexadecane,
Linear saturated hydrocarbon iodides such as iodoheptadecane, iodooctadecane, iodononadecane, iodoeicosane; branched saturated hydrocarbons such as 2-iodobutane, 1-iodo-2-methylpropane, 1-iodo-3-methylbutane, etc. Iodide; iodobenzyl, iodophenocil, 3-iodo-1
- Cyclic unsaturated hydrocarbon iodides such as cyclohexene; cyclic saturated hydrocarbon iodides such as iodocyclopentane, iodocyclohexane, 1-iodo-3-methylcyclohexane, iodocycloheptane, and iodocyclooctane. A typical synthesis example of the optically active alcohol represented by the formula () is shown below. Example 1 Synthesis of 2-butoxypropanol (x=0, y
=1, R=n- _C4H9- ) 31.5 g of L-(+)-ethyl lactate and 107.3 g of 1-iodobutane were mixed into _a four-toned flask, and the newly synthesized _Ag2O was added over 2 hours. After standing at room temperature for 15 hours, the mixture was diluted with 200 ml of ether, and the ether was distilled off. 5% KOH aqueous solution 100%
ml, dried over anhydrous Na ₂ SO ₄ and distilled under reduced pressure, and fractions at 110° C./54 mmHg were collected to obtain 23 g of (-)-ethyl-2-butoxypropionate. Optical rotation [α] 24° D = -73°. 2.0 g of LiAlH ₄ was added to 100 ml of ether and stirred for 3 hours, to which 12.7 g of (-)-ethyl-2-butoxypropionate was added dropwise. 15 after completion of dripping
Stirring was continued for several minutes. Then 50ml of water and 10%
50 ml _{of H2SO4} aqueous solution was added. The ether layer was separated and dried over MgSO ₄ . The ether was distilled off. Yield 7.4g, optical rotation [α] 24° D=+
24.4°. Example 2 Synthesis of 3-pentyloxybutanol (x=
0, y=2, R=n- _C5H11- ) (R)-(- ₎ -3-hydroxybutyrate methyl 92.1
g and 389 g of pentyl iodide were mixed into a flask under a stream of _N2 . Add 271g of newly synthesized Ag ₂ O, stir at 60-65℃ for 26 hours, and further
54.2 g of Ag ₂ O was added and stirred at 60-65°C for 58 hours.
After evaporation, the filtrate was thoroughly washed with ether, the ether in the liquid was distilled off, and then distilled under reduced pressure to 112-131℃/
64.6 g of methyl 3-pentyloxybutyrate was obtained as a fraction at 59 mmHg. Next, add 9.4 g of LiAlH ₄ to 310 ml of ether,
A solution of 63.6 g of methyl 3-pentyloxybutyrate in 61 ml of ether was added dropwise at 10° C. or below over 2 hours. After stirring for 2.5 hours at 20-25℃ after dropping,
I left it for a while. Thereafter, the mixture was acidified with an aqueous hydrochloric acid solution (PH1) and extracted with ether. Add ether layer to water, 5%
It was washed with NaHCO ₃ aqueous solution and water in that order, and dried with MgSO ₄ . Distilled under reduced pressure at 127-131℃/50mm
34.2 g of 3-pentyloxybutanol was obtained as a Hg fraction. Regarding the product, the following
IR data was obtained. IR (cm ^-1 ): 3360, 2970~2870, 1370, 1090. Example 3 Synthesis of 3-ethyloxy-2-methylpropanol (x=1, y=1, R=C ₂ H ₅ −) 100 g of methyl (R)-(−)-3-hydroxy-2-methylpropionate and iodine 331 g of ethyl chloride was added to the flask and mixed under a stream of _N2 . 294 g of newly synthesized Ag ₂ O was added and stirred at 60-65°C for 20 hours. After evaporation, the filtrate was washed with ether, the ether in the liquid was distilled off, and then distilled under reduced pressure.
87 g of methyl 3-ethyloxy-2-methylpropionate was obtained as a fraction at °C/150 mmHg. Next, add 18.5g of LiAlH ₄ to 610ml of ether,
A solution of 87 g of methyl 3-ethyloxy-2-methylpropionate in 122 ml of ether was added dropwise at 10° C. or below over 6 hours. After the dropwise addition, the mixture was stirred at 20 to 25°C for 2.5 hours, and then left at room temperature for 15 hours. 5% thereafter
The mixture was made acidic with an aqueous hydrochloric acid solution and extracted with ether. The ether layer was washed sequentially with water, 5% NaHCO ₃ aqueous solution, and water, and dried over MgSO ₄ . After distilling off the ether,
Distillation was carried out under reduced pressure to obtain 39 g of 3-ethyloxy-2-methylpropanol as a fraction at 110-115° C./155 mmHg. IR: (cm ^-1 ): 3380, 2980~2870, 1380, 1110, 1040. Example 4 4-n-octyloxypentanol (x=
0, y=3, R=n- _C8H17- ) L(+)-ethyl lactate 98g, octyl iodide ₃₈₀
g and 245 g of silver oxide were added thereto, and the mixture was stirred at 60° C. for 16 hours. After filtering out insoluble matter, distill under reduced pressure to 110-130
77 g of ethyl 2-octyloxypropionate was obtained as a fraction of °C/3 mmHg. Next, 7.5 g of LiAlH ₄ in 250 ml of diethyl ether
After stirring for a while, a solution of 56 g of the above ester in 50 ml of diethyl ether was added dropwise at below 5°C over 2 hours. After the dropwise addition, the mixture was stirred at room temperature for 2 hours, and then
It was left for 15 hours. After the reaction is complete, add 30 ml of 5% hydrochloric acid, and make the mixture acidic (pH ~ 1) with 6N hydrochloric acid.
Extracted with ether. After washing with water, it was dried and the solvent was distilled off. Distillation was carried out under reduced pressure to obtain 39.5 g of 2-octyloxypropanol as a fraction at 107°C/3 mmHg. Next, 230 ml of pyridine was added to 70 g of the above alcohol, and 85 g of tosyl chloride was added thereto over 30 minutes at 10° C. or below while stirring. After stirring at this temperature for 15 minutes, the temperature was raised and the mixture was stirred at 20-24°C for 3.5 hours. After pouring into cold water, it was extracted with benzene, washed with 5% hydrochloric acid and water in that order, and dried. Benzene was distilled off and (2-octyloxypropyl)p-toluenesulfonate
Obtained 127g. Add 26.7 g of 95% sodium ethoxide to 220 ml of ethanol, and add 98% diethyl malonate while stirring.
73.1 g was added dropwise over 50 minutes at 36-38°. moreover
After stirring for 30 minutes, 127 g of the above Toshile compound was added dropwise at 36 to 38°C over 1 hour. After stirring for an additional 15 minutes, the mixture was heated and refluxed for 18 hours. After the reaction, ice water was poured into the reaction mixture, extracted with benzene, washed with water, and then dried. The solvent is distilled off,
149 g of ethyl 4-octyloxy-2-ethoxycarbonylvalerate was obtained. Next, dissolve 88.5g of 85% KOH in 90ml of water,
149 g of the above ester was added dropwise at 20 to 25°C over 50 minutes, stirred for 30 minutes, and then refluxed for 2 hours. After cooling, 15
Keeping the temperature below ℃, dissolve 153 g of concentrated sulfuric acid in 196 ml of water,
This was added dropwise over 1 hour. After stirring for 30 minutes, the mixture was refluxed for 3 hours. After cooling to room temperature, the mixture was extracted with benzene. Wash the benzene layer with 5% NaOH aqueous solution,
added to the aqueous layer. The aqueous layer was acidified (PH1) with 6N hydrochloric acid, extracted with benzene, washed with water, and dried over anhydrous MgSO ₄ . The solvent was distilled off to obtain 54 g of 4-octyloxyvaleric acid. 10 g of LiAlH ₄ was added to 210 ml of dry ether, and while stirring, a solution of 54 g of the above carboxylic acid in 70 ml of ether,
The mixture was added dropwise over 70 minutes while maintaining the temperature at 2 to 6°C. After dropping, the temperature was raised to 23°C and stirred for 3 hours. After standing for 12 hours, add 5% hydrochloric acid while keeping the temperature below 15℃ to make it acidic, then extract with ether, add water and 5%
It was washed successively with NaOH aqueous solution and water, and dried with anhydrous MgSO ₄ . The solvent was distilled off, then distilled under reduced pressure, and the
10 g of (S)-4-octyloxypentanol was obtained as a fraction at °C/5 mmHg. IR (cm ^-1 ): 3360, 2970~2860, 1460, 1370, 1340, 1080. An optically active liquid crystal compound represented by the general formula () can be obtained using the optically active alcohol represented by the general formula () and according to the reaction scheme shown below.

[Table] The liquid crystal composition of the present invention contains at least one optically active liquid crystal compound represented by the above general formula ().
It is contained as a type compounding component. Among the above compositions, those containing ferroelectric liquid crystals as represented by the following formulas (1) to (13) can increase spontaneous polarization and further reduce viscosity. It is preferable that this combination can improve the response speed. In such cases, the optically active liquid crystal compound of the present invention represented by the general formula () may be used in a proportion of 0.1 to 99% by weight, particularly 1 to 90% by weight of the resulting liquid crystal composition. preferable.

【table】

【table】

[Table] Furthermore, by blending with a smectic liquid crystal which is not chiral itself as shown in the following formulas (1) to (5), a composition usable as a ferroelectric liquid crystal can be obtained. In this case, the liquid crystal composition from which the optically active liquid crystal compound of the present invention represented by the general formula () can be obtained.
It is preferred to use 0.1 to 99% by weight, especially 1 to 90% by weight.

【table】

[Table] In addition, the optically active liquid crystal compound of the general formula () above can be added to a nematic liquid crystal to
This is effective in preventing the occurrence of reverse domains in TN cells. In this case, the optically active liquid crystal compound of the formula () may be used in an amount of 0.01 to 50% by weight of the liquid crystal composition obtained by adding the optically active liquid crystal compound of the formula () to the nematic liquid crystal. preferable. Furthermore, by adding it to a nematic liquid crystal or a chiral nematic liquid crystal, it can be used as a liquid crystal composition in a phase change type liquid crystal element or a White-Taylor type guest-host type liquid crystal element. Figure 1 is for explaining the operation of ferroelectric liquid crystal.
This is a schematic drawing of an example of a cell. 11a
and 11b are In ₂ O ₃ , SnO ₂ or
A substrate (glass plate) covered with a transparent electrode ^made of a thin film of ITO (Indium-Tin Oxide), etc., between which a liquid crystal molecular layer 12 is oriented perpendicular to the ^glass surface. A liquid crystal is enclosed. A thick line 13 represents a liquid crystal molecule, and this liquid crystal molecule 13 has a dipole moment (P⊥) 14 in a direction perpendicular to the molecule. When a voltage higher than a certain threshold is applied between the electrodes on the substrates 21 and 11b, the helical structure of the liquid crystal molecules 13 is unraveled, and the dipole moment (P ⊥) 14
The alignment direction of the liquid crystal molecules 13 can be changed so that all of the liquid crystal molecules are oriented in the direction of the electric field. The liquid crystal molecules 13 are
It has an elongated shape and exhibits refractive index anisotropy in its major and minor axis directions. Therefore, for example, if crossed Nicol polarizers are placed above and below the glass surface,
It is easily understood that this is a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of applied voltage. The liquid crystal cell preferably used in the optical modulation element of the present invention can have a sufficiently thin thickness (for example, 10 μm or less). As the liquid crystal layer becomes thinner in this way, the helical structure of the liquid crystal molecules unravels even when no electric field is applied, as shown in Figure 2, and the dipole moment Pa or Pb is either upward 24a or downward 24b. takes the state of When an electric field Ea or Eb of different polarity above a certain threshold value is applied to such a cell by the voltage applying means 21a and 21b as shown in FIG. 2, the dipole moment corresponds to the electric field vector of the electric field Ea or Eb. The liquid crystal molecules change direction to upward 24a or downward 24b, and accordingly the liquid crystal molecules enter the first stable state 2.
3a or the second stable state 23b.
Orient towards. As mentioned earlier, there are two advantages to using such ferroelectricity as an optical modulation element. The first is that the response speed is extremely fast, and the second is that the alignment of liquid crystal molecules has bistability. To further explain the second point, for example, with reference to FIG. 2, when an electric field Ea is applied, the liquid crystal molecules are oriented in a first stable state 23a, and this state remains stable even when the electric field is turned off. Also, the electric field in the opposite direction
When Eb is applied, the liquid crystal molecules enter the second stable state 2
3b and changes the direction of the molecule, but it remains in this state even when the electric field is turned off. Further, as long as the applied electric field Ea or Eb does not exceed a certain threshold value, the previous 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, generally 0.5μ to 20μ, especially 1μ.
~5μ is 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 scan electrode S ₁
The following describes the case where is selected. FIG. 4a and FIG. 4b are scanning signals, which are electrical signals applied to the selected scanning electrode S ₁ and the other scanning electrodes (unselected scanning electrodes) S ₂ , S ₃ , and S ₄ respectively. It shows an electrical signal applied to... Figures 4c and 4d show information signals from selected signal electrodes I ₁ , I ₃ , I ₅ and unselected signal electrodes I ₂ , I _{4 ,} respectively.
It shows the electrical signal given to the In FIGS. 4 and 5, the horizontal axis represents time and the vertical axis represents voltage, respectively. For example, when displaying a moving image, the scanning electrode group 32 sequentially
Selected periodically. Now, the predetermined voltage application time t ₁
or of a liquid crystal cell with bistability for t ₂ ,
The threshold voltage for giving the first stable state is -
When Vth _{is 1} and the threshold voltage for providing a stable state of 2 is +Vth ₂ , the selected scan electrode 32
The electrode signal applied to (S ₁ ) is a voltage that alternates between 2V at phase (time) t ₁ and -2V at phase (time) t ₂ as shown in Figure 4a. . 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 a state change can be caused quickly. On the other hand, the other scanning electrodes S ₂ to S ₅ are in a grounded state as shown in FIG. 4b, and have an electrical signal of 0. Also, the selected signal electrodes I ₁ , I ₃ , I ₅
The electric signal applied to the unselected signal electrodes I 2 and I 4 is -V as shown in FIG. 4c, and the electric signal applied to the unselected signal electrodes I ₂ and I ₄ is -V as shown in FIG. In the above, each voltage value is set to a desired value that satisfies the following relationship. V<Vth ₂ <3V -3V<-Vth ₁ <-V Among the pixels when such an electric signal is applied, for example, the voltage waveforms applied to pixels A and B in FIG. Shown in Figure 5 a and b. That is, as is clear from FIGS. 5a and 5b, at the pixel A on the selected scanning line, the threshold value is reached at phase _t2 .
A voltage of 3V exceeding Vth ₂ is applied. Furthermore, a voltage of -3V exceeding the threshold value _-Vth1 is applied to the pixel B existing on the same scanning line at phase _t1 . Therefore,
On the selected scanning electrode line, depending on whether a signal electrode is selected or not, if selected, the liquid crystal molecules are aligned in the first stable state, and if not selected, the liquid crystal molecules are aligned in the second stable state. Align the orientation to a stable state. On the other hand, as shown in FIGS. 5c and 5d, on unselected scanning lines, the voltages applied to all pixels are either V or -V, neither of which exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel other than on the selected scanning line maintain the orientation corresponding to the signal state when scanned last time 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 remains unchanged and the contrast does not deteriorate at all. Next, let's consider the problems that may actually occur when the device is driven as a display device. In FIG. 3, scanning electrodes S ₁ to S ₅ ... and signal electrodes I ₁ to _{I 5}
Among the pixels formed at the intersections of ..., the pixels in the shaded area correspond to the "bright" state, and the pixels shown in white correspond to the "dark" state. Now, the signal electrode I ₁ in Fig. 3
Paying attention to the above display, the pixel (A) corresponding to the scanning electrode S ₁ is in a "bright" state, and all other pixels (B) are in a "dark" state. As an example of the driving method in this case, FIG. 6 shows a time series representation of the scanning signal, the information signal applied to the signal electrode _I1 , and the voltage applied to the pixel A. For example, when driven as shown in FIG. 6, when the scanning signal S ₁ is scanned, the pixel A at time t ₂
Since a voltage of 3V exceeding the threshold value Vth ₂ is applied to , the pixel A transitions (switches) to a stable state in one direction, that is, a "bright" state, regardless of the previous history. After that, while S ₂ to _{S 5} ... are being scanned, the voltage of -V continues to be applied as shown in Figure 6, but since this does not exceed the threshold -Vth ₁ , pixel A remains in the "bright" state. However, in reality, one signal (in this case "dark") can be maintained on one signal electrode.
When displaying information that is continuously given (corresponding to
By using the above-mentioned specific liquid crystal compound or a liquid crystal composition containing the same, such an inversion 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 made 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, silicon nitride containing hydrogen, silicon carbide, silicon carbide containing hydrogen, silicon oxide, boron nitride, and hydrogen. Inorganic insulating materials such as boron nitride, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide and magnesium fluoride, or polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylene, polyester, Organic insulating materials such as polycarbonate, 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 thickness of these insulating films is 5000 Å or less, preferably 100 Å or more.
1000 Å, especially 500 Å to 3000 Å are suitable. Hereinafter, the present invention will be explained in more detail with reference to Examples. Synthesis Example 4 Synthesis of 4-(2-n-propoxypropyloxy)phenyl-4′-(4″-n-octyloxybenzoyloxy)benzoate. (Step) 1 Synthesis of p-hydroquinone mono(2-propoxypropyl) ether . To a mixture of 140 ml of dry pyridine and 27.5 g of 2-propyloxypropanol and cooled on ice, 53.5 g of p-toluenesulfonic acid chloride was added over 30 minutes, and after returning to room temperature, the mixture was stirred for 6 hours, and further stirred for 15 hours. The reactant was added to cold water, extracted with benzene, and dried over anhydrous Na ₂ SO _4. Benzene was distilled off to obtain 59 g of oily (2'-propoxypropyl)-p-toluenesulfonate. Next, 35.9 g of hydroquinone and 14.9 g of 85% KOH were added together with 318 ml of ethanol and 62 ml of methanol.
Stirred for 5 hours. To this, 59 g of 2'-propoxypropyl-p-toluenesulfonate obtained above
was added and reacted at 60°C for 2 hours, under reflux at 76-78°C for 5 hours, and then cooled. The reaction mixture was added while cooling with ice, and then acidified with hydrochloric acid. After extraction with n-hexane, sequential washing treatment with 5% NaOH aqueous solution and water was performed, and then n-
Hexane was distilled off to obtain crystals. Further recrystallization was performed using n-hexane to obtain 13.6 g of p-hydroquinone mono(2-propoxypropyl) ether. (Step) 2 Synthesis of 4-(2-n-propoxypropyloxy)phenyl-4'-hydroxybenzoate. 5 g of p-hydroquinone mono(2-propoxypropyl) ether and p-hydroxybenzoic acid
Dissolve 2.7g in 100ml of toluene, and add concentrated sulfuric acid to this.
0.1 g of boric acid and 0.06 g of boric acid were added, and the mixture was heated to 110 to 115°C, and the reaction was carried out by reflux dehydration for 18 hours. It was then cooled and poured into cold water. After extraction with ether and washing with a 5% NaOH aqueous solution and water, the ether was distilled off. The obtained oil was dissolved in bezene, treated with an activated carbon column, and then benzene was distilled off to obtain 2.5 g of 4-(2-n-propoxypropyloxy)phenyl-4'-hydroxybenzoate. (Step 3) Synthesis of 4-(2-n-propoxypropyloxy)phenyl-4'-(4''-n-octyloxybenzoyloxy)benzoate. 4-(2-n-propoxypropyloxy)phenyl-4' - To a solution of 1.5 g of hydroxybenzoate in 15.5 ml of pyridine, add 10 ml of toluene of p-n-octyloxybenzoic acid chloride (synthesized from 1.2 g of p-n-octyloxybenzoic acid).
After adding the solution and stirring at room temperature for 1 hour,
Stir at ℃ for 2 hours and cool. The reaction solution was added to cold water, extracted with ether, extracted with 5% hydrochloric acid, water, 5%
After sequentially washing with % NaOH aqueous solution and water, the ether was distilled off and the obtained crystals were recrystallized with ethanol to obtain 0.8 g of white crystals. The phase transition temperature of the product is shown below. Cryst.70 ――→ ←―― 47SmA143 ―――→ ←―――― 140Ch.148 ――――→ ←――― 145Iso. The following compounds were synthesized in the same way. 4-(2-Methyloxypropyloxy)phenyl-4'-(4''-n-decyloxybenzoyloxy)benzoate, 4-(2-ethyloxypropyloxy)phenyl-4'-(4''-n-hexyl) Oxybenzoyloxy)benzoate, 4-
(2-butyloxypropyloxy)phenyl-
4′-(4″-n-heptyloxybenzoyloxy)
Benzoate, 4-(2-pentyloxypropyloxy)phenyl-4'-(4''-n-octylbenzoyloxy)benzoate, 4-(2-octyloxypropyloxy)phenyl-4'-
(4″-trans-propylcyclohexylcarbonyloxy)benzoate, 4-(3-heptyloxybutyloxy)phenyl-4′-(4″-n-
Decyloxybenzoyloxy)benzoate,
4-(4-propyloxypentyloxy)phenyl-4'-(4'-trans-n-hexylcyclohexylcarbonyloxy)benzoate, 4-
(6-butyloxyheptyloxy)phenyl-
4'-(4''-propylbenzoyloxy)benzoate, 4(2-methyl-3-ethyloxypropyloxy)phenyl-4'-(4''-n-hexyloxybenzoyloxy)benzoate. Example 1 1 part by weight of 4-(2-n-propoxypropyloxy)phenyl-4′-(4″-n-octyloxybenzoyloxy)benzoate was added to 99 parts by weight of Rixon GR-63 (biphenyl liquid crystal mixture manufactured by Chitsuso). A TN cell using a liquid crystal mixture containing this optically active liquid crystal compound has uneven color tone (reverse domain) due to the liquid crystal region, which was confirmed by polarized light microscopy observation of a TN cell manufactured without adding this optically active liquid crystal compound. Example 2 Opposing matrix electrodes formed of intersecting strips of ITO were each coated with a polyimide film (with pyromellitic anhydride and 4,4 A 5% by weight N-methylpyrrolidone solution of polyamic acid resin consisting of a bond with '-diaminodiphenyl ether was coated, and a layer (formed by a ring-closing reaction under heating at a temperature of 250°C) was provided, and the surfaces of this polyimide film were bonded to each other. A cell with a cell thickness of 1 μm was prepared by rubbing so that the cells were parallel to each other. Next, the following composition A was injected into the above-mentioned cell under an isotropic phase by a vacuum injection method, and the cell was sealed. A liquid crystal cell of SmC ^* was prepared by slow cooling (1° C./hour). A crossed nicol polarizer and an analyzer were placed on both sides of this liquid crystal cell, and signals having the waveforms shown in FIGS. 4 and 5 were applied between opposing matrix electrodes. At this time, the scanning signals are +8 volts and -8 volts as shown in Figure 4a.
An alternating voltage waveform was used, and the written information was set to +4 volts and -4 volts, respectively. In addition, one frame period was set to 30 m·sec. As a result, even when this liquid crystal element was subjected to the above-described memory-driven time-division driving, the written state was not reversed and a normal moving image display was obtained. Comparative Example 1 The following comparative liquid crystal B was obtained by omitting the optically active liquid crystal compound represented by the above-mentioned general formula () in the liquid crystal composition used to create the liquid crystal element of Example 2.
was prepared, and a liquid crystal element was created using the comparative liquid crystal. Although these liquid crystal elements were driven in the same manner as described above, a normal moving image could not be displayed due to an inversion phenomenon. Examples 3 to 12 1 part by weight of 4-(2-n-propoxypropyloxy)phenyl-4′-(4″-n-octyloxybenzoyloxy)benzoate in Example 1 was replaced with 4-(2-methyloxy), respectively. Propyloxy)phenyl-4'-(4''-n-decyloxybenzoyloxy)benzoate, 4-(2-ethyloxypropyloxy)phenyl-4'-
(4″-n-hexyloxybenzoyloxy)benzoate, 4-(2-butyloxypropyloxy)phenyl-4′-(4″-n-heptyloxybenzoyloxy)benzoate, 4-(2-pentyloxypropyloxy) ) phenyl-4′-
(4″-n-octylbenzoyloxy)benzoate, 4-(2-octyloxypropyloxy)
Phenyl-4′-(4″-trans-propylcyclohexylcarbonyloxy)benzoate, 4-
(3-heptyloxybutyloxy)phenyl-
4′-(4″-n-decyloxybenzoyloxy)
Benzoate, 4-(4-propyloxypentyloxy)phenyl-4'-(4'-trans-n-
hexylcyclohexylcarbonyloxy)benzoate, 4-(6-butyloxyheptyloxy)phenyl-4'-(4''-propylbenzoyloxy)benzoate, 4(2-methyl-3-ethyloxypropyloxy)phenyl-4'- (4″−
Experiments similar to those in Example 1 were conducted except that 1 part by weight of n-hexyloxybenzoyloxy)benzoate was used (Examples 3 to 12). As a result, in the TN cell manufactured without adding this optically active liquid crystal compound, unevenness in color tone (reverse domain) due to the liquid crystal region, which was confirmed by polarized light microscopy, was observed in the microscopic field of view for the cells of all examples. An imperceptible decrease was observed within the range. Examples 13-22 In Example 2 12% by weight of 4-(2-methyloxypropyloxy)phenyl-4′-(4″-n-decyloxybenzoyloxy)benzoate, 4
-(2-ethyloxypropyloxy)phenyl-4'-(4''-n-hexyloxybenzoyloxybenzoate, 4-(2-butyloxypropyloxy)phenyl-4'-(4''-n-heptyloxybenzoyl) oxy)benzoate, 4-(2
-Pentyloxypropyloxy)phenyl-
4′-(4″-n-octylbenzoyloxy)benzoate, 4-(2-octyloxypropyloxy)phenyl-4′-(4″-trans-propylcyclohexylcarbonyloxy)benzoate, 4-(3-heptyloxy) butyloxy)phenyl-4'-(4''-n-decyloxybenzoyloxy)benzoate, 4-(4-propyloxypentyloxy)phenyl-4'-(4'-trans-n-hexylcyclohexylcarbonyloxy)benzoate , 4-(6-butyloxyheptyloxy)phenyl-4′-(4″-propylbenzoyloxy)benzoate, 4(2-methyl-
3-ethyloxypropyloxy)phenyl-
4′-(4″-n-hexyloxybenzoyloxy)
Experiments similar to those in Example 2 were conducted using liquid crystal compositions and devices by replacing benzoate with 12% by weight (Examples 13 to 22). As a result, even if these liquid crystal elements perform the aforementioned memory-driven time-division driving, the written state is
A normal video display was obtained without any inversion.

[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. 4 a to d are , FIGS. 5a to 5d are explanatory diagrams showing the waveforms of the voltages applied between the matrix electrodes, and FIG. 6 is an explanatory diagram showing the electric signals applied to the liquid crystal element of the present invention. FIG. 2 is an explanatory diagram of a time chart showing signals. 11a, 11b...substrate, 12...liquid crystal molecule layer, 13...liquid crystal molecule, 14...dipole moment (P⊥), 23a...first stable state, 23b
... second stable state, 24a ... upward dipole moment, 24b ... downward dipole moment,
31...Cell, 32...( _S1 , _S2 , _S3 ,...)...Scanning electrode group, 33...( _I1 , _I2 , _I3 ,...)...Signal electrode group.

Claims (1)

[Claims] 1. The following general formula () (However, R represents an alkyl group having 1 to 8 carbon atoms, C ^* represents an optically active asymmetric carbon atom, R ¹ represents an alkyl group or an alkoxy group having 3 to 10 carbon atoms, and [Formula] is , [Formula] or [Formula], x is 0 or 1, and y is 1 to 5. 2 General formula below () (However, R represents an alkyl group having 1 to 8 carbon atoms, C ^* represents an optically active asymmetric carbon atom, R ¹ represents an alkyl group or an alkoxy group having 3 to 10 carbon atoms, and [Formula] is , [Formula] or [Formula], x is 0 or 1, and y is 1 to 5.