JPH0228291A - Liquid crystal composition and liquid crystal element containing the same composition - Google Patents

Abstract

PURPOSE:To provide a ferroelectric chiral smectic liquid crystal composition containing two specific kinds of compounds, having good switching characteristics and large driving voltage margin and capable of keeping the image in good state even if the display area of the element has a temperature distribution. CONSTITUTION:The objective composition contains (A) at least one kind of the compound of formula I [R1 is 1-18C (substituted) alkyl; R2 is 1-12C straight- chain alkyl; X1 is single bond, -O-, -OC(O)-, -C(O)O- or -OC(O)O-; the rings A and B are p-phenylene, p-cyclohexane or group of formula II] (e.g., the compound of formula III) and (B) at least one kind of the compound of formula IV [R3 and R4 are 1-18C (substituted) alkyl provided that at least one of R3 and R4 is optically active; X3 is X1] (e.g., the compound of formula V).

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a liquid crystal composition used for liquid crystal elements used in liquid crystal display elements, liquid crystal light shutters, etc. This invention relates to a liquid crystal composition.

[Background technology]

Conventionally, liquid crystals have been applied as electro-optical elements in a variety of fields. Most of the liquid crystal elements currently in practical use are, for example, those written by M, 5chadt and W, "Applied Physics Letters" by Helfrich.
Vo, 1B, No. 4 (1971, 2, 15), P
, 127-128 “Voltage-5 penden
t 0ptical Activity of
aTwisted Nematic Liquid
T N (t w i s
This uses a type of liquid crystal.

These are based on the dielectric alignment effect of liquid crystals, and due to the dielectric anisotropy of liquid crystal molecules, the average molecular axis direction is oriented in a specific direction by an applied electric field. It is said that the limit of the optical response speed of an element is milliseconds, which is too slow for multi-purpose applications.On the other hand, for applications in large flat displays, the simple matrix method is recommended in terms of cost, productivity, etc. In the simple matrix method, an electrode configuration in which a scanning electrode group and a signal electrode group are arranged in a matrix is adopted.
To drive this, a time-division drive method is adopted in which address signals are selectively and periodically applied to the scanning electrode group, and predetermined information signals are selectively applied in parallel to the signal electrode group in synchronization with the address signal. be done.

However, if the above-mentioned TN type liquid crystal is used as an element of such a driving method, there will be an area where the scanning electrode is selected and the signal electrode is not selected, or an area where the scanning electrode is not selected and the signal electrode is selected (the so-called "half area"). A finite electric field is also applied to the selected point ("). If the difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large, and the voltage threshold required to align the liquid crystal molecules perpendicular to the electric field is set to an intermediate voltage value, the display element will It works normally, but if you increase the number of scanning lines (N), the entire screen (
The time during which an effective electric field is applied to one selected point (duty ratio) decreases at a rate of l/N while scanning one frame. For this reason, the effective voltage difference between selected points and non-selected points when repeated scanning is
As the number of scanning lines increases, the size becomes smaller, resulting in unavoidable drawbacks such as "reduction in image contrast" and crosstalk.

This phenomenon is caused by liquid crystals that do not have bistability (the stable state is when the liquid crystal molecules are aligned horizontally with respect to the electrode surface, and they are aligned vertically only while an electric field is effectively applied). ) is essentially an unavoidable problem that arises when driving using the temporal accumulation effect (that is, repeatedly scanning). In order to improve this point, voltage averaging method, dual-frequency driving method, multiple matrix method, etc. have already been proposed, but all of these methods are insufficient, and it is necessary to increase the screen size and density of display elements. Currently, the number of scanning lines has reached a plateau due to the inability to increase the number of scanning lines sufficiently.

In order to improve the drawbacks of conventional liquid crystal elements, the use of bistable liquid crystal elements has been proposed for C1ark and L
proposed by Agerwall (Japanese Unexamined Patent Application Publication No. 1983-1999)
107216, US Pat. No. 4,367,924, etc.). A ferroelectric liquid crystal having a chiral metal C phase (SmC*) or H phase (SmH tree) is generally used as the bistable liquid crystal. This ferroelectric liquid crystal has a bistable state consisting of a first optically stable state and a second optically stable state in response to an electric field, and therefore is different from the optical modulation element used in the above-mentioned TN type liquid crystal. Differently, for example, the liquid crystal is oriented in a first optically stable state with respect to one electric field vector, and the liquid crystal is oriented in a second optically stable state with respect to the other electric field vector. Furthermore, this type of liquid crystal has a property (bistability) of 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.

In addition to the above-mentioned feature of bistability, ferroelectric liquid crystals have the excellent feature of high-speed response. This is because the spontaneous polarization of the ferroelectric liquid crystal and the applied electric field directly act to induce a transition in the orientation state, which is 3 to 4 orders of magnitude faster than the response speed due to the effect of the dielectric anisotropy and the electric field.

In this way, ferroelectric liquid crystals potentially have extremely excellent properties, and by utilizing these properties, many of the problems of conventional TN-type devices mentioned above can be overcome, which is quite essential. Improvement can be obtained.

In particular, it is expected to be applied to high-speed optical shutters and high-density, large-screen displays.

In the case of a simple matrix display device as described above using an element in which this ferroelectric liquid crystal layer is sandwiched between a pair of substrates, for example, Japanese Patent Laid-Open Nos. 59-193426 and 59-193 disclose
No. 427, No. 60-156046 and No. 60-
The driving method disclosed in Japanese Patent No. 156047 and the like can be applied.

FIG. 4 is a waveform diagram of the driving method used in the embodiment of the present invention. Further, FIG. 5 is a plan view of a ferroelectric liquid crystal panel 51 on which matrix electrodes used in the present invention are arranged. Fifth
In the panel 51 shown in the figure, a scanning line 52 and a data line 53 are wired to cross each other, and a ferroelectric liquid crystal is disposed between the scanning line 52 and the data line 53 at the intersection.

In FIG. 4(A), SS is the selection scanning waveform applied to the selected scanning line, SN is the unselected scanning waveform, and Is is the selection information waveform (black) applied to the selected data line. ), IN represents a non-selection information signal (white) applied to an unselected data line. Also, in the figure (Is
Ss) and (IN SS) are the voltage waveforms applied to the pixels on the selected scanning line, and the pixels to which the voltage (Is Ss) is applied display black, and the voltage (IN SS) is applied to the pixels on the selected scanning line.
The pixel to which S) is applied assumes a white display state.

FIG. 4(B) is a time series waveform when the display shown in FIG. 6 is performed using the drive waveform shown in FIG. 4(A).

In the driving example shown in FIG. 4, the minimum application time Δt of the unipolar voltage applied to the pixels on the selected scanning line corresponds to the time of the write phase t2, and the l line clear 1. The phase time is set to 2Δt.

Now, each parameter Vs, V of the drive waveform shown in FIG.
, , Δt is determined by the switching characteristics of the liquid crystal material used.

In FIG. 7, the transmission when the driving voltage (Vs+V+) is changed while keeping the bias ratio, which will be described later, constant is fixed at s + 1/3. The positive side of Figure 7 is shown in Figure 4 (IN ss), and the negative side is (I
8SS) is applied. Here, vl +
v3 are called an actual drive threshold voltage and a crosstalk voltage, respectively. However, V2<V, <V3) and △V”(V3
Vl) is called a voltage margin and is a voltage width that allows matrix drive. It can be said that v3 generally exists in FLC matrix drive.

Specifically, this is the voltage value that causes switching due to vB' in the waveform of FIG. 4(A) (IN SS). Of course, it is possible to increase the value of v3 by increasing the bias ratio, but increasing the bias ratio means increasing the amplitude of the information signal, which may lead to an increase in flickering and a decrease in contrast in terms of image quality. In our study, a bias ratio of about 1/3 to 1/4 is practical. By the way, if the bias ratio is fixed, the voltage margin △V is strongly influenced by the switching characteristics of the liquid crystal material (depending on the switching characteristics of the liquid crystal material). However, it goes without saying that a liquid crystal material with a large ΔV is very advantageous for matrix driving.

At a certain temperature like this, it is possible to write two states, "black" and "white", into the selected pixel by changing the two directions of the information signal, and unselected pixels can write the "black" or "white" state into the selected pixel. The upper and lower limits of the applied voltage that can maintain this state and their widths (driving voltage margin ΔV) differ between liquid crystal materials and are unique. The drive margin also changes due to changes in the environmental temperature (therefore, in the case of actual display devices, it is necessary to set the drive voltage optimally for the liquid crystal material and the environmental temperature).

However, in practice, when the display area of such a matrix display device is expanded, the difference in the environment in which the liquid crystal exists in each pixel (specifically, the temperature and the cell gap difference between electrodes) naturally increases, and the driving With a liquid crystal display having a small voltage margin, it is not possible to obtain a good image over the entire display area.

[Problem that the invention seeks to solve]

In order to put ferroelectric liquid crystal elements into practical use, the present invention has a large drive voltage margin and a wide drive temperature margin that allows all pixels to be satisfactorily driven in matrix even if there is a certain degree of temperature variation over the display area of the liquid crystal element. An object of the present invention is to provide a chiral smectic liquid crystal composition and a liquid crystal element using the liquid crystal composition.

[Means for solving the problem] The present invention is based on the following general formula (I), where R1 is a linear or branched alkyl group which may have a C1 to CI8 substituent, and R2 is a C1 to C1 □
a straight-chain alkyl group, Xl is a single bond, and at least one of the compounds represented by -0- and the following general formula (II). It is a chain or branched alkyl group.

However, at least one of them is optically active. A ferroelectric chiral smectic liquid crystal composition characterized by containing at least one compound represented by X 2 + and a liquid crystal element formed by disposing the liquid crystal composition between a pair of electrode substrates. It is.

Among the compounds represented by the aforementioned general formula (1), preferred examples include those represented by general formulas (1-a) to (1-d).

Furthermore, X in the above formulas (I-a) to (1-d)
A more preferable example of R3 is a single bond, and a more preferable example of R3 in the above formulas (1-a) to (I d) is a linear alkyl group.

Further, among the compounds represented by the above-mentioned general formula (II), preferred examples of compounds include X2. x3 is (II −i
) to (II-viii).

(II-i) X2 is a single bond, X3 is -〇 (II-ii) X2 is a single bond, X3 is
-0C-〇(II-iii) X 2 is a single bond,
X3 is -CO-(II-4v)X2 is a single bond, X3 is a single bond (II-v)X2 is 10-1
X3 10 (II-vi) X2 10-1X3 10C
-(II-vii) X 2 is -0-1x3 is -CO
-(II-viii) X 2 is a single bond,
x3 is a single bond Furthermore, preferable examples of compounds for R3 and R4 in the compound represented by the general formula (II) include (TI-ix) to (II-xi).

(II-1x) R3 is an n-alkyl group.

CH3 R4 is (-CH2) x CH-Rs * CH3 R4 is (-CH2 arrow x CH * 　6　r (x + y is O~7, is a straight chain or branched alkyl group) The above general formula The specific structure of the compound shown in An example of the construction formula is shown below.

■ ■ ■! -38 ■-46 ■-53 Synthesis Example 1 (Synthesis of Compound No. 1-4) (■) Trans-4-n-propylcyclohexanecarboxylic acid chloride log (53,6 mmol in ethanol 30 ml
A small amount of triethylamine was added thereto, and the mixture was stirred at room temperature for 10 hours. Pour the reaction mixture into 100mj of ice water! After adding 6N hydrochloric acid aqueous solution to make it acidic, the mixture was extracted with isopropyl ether. The organic layer was washed with water repeatedly until the washing liquid became neutral, and then dried with magnesium sulfate. After distilling off the solvent, the residue was purified by silica gel column chromatography to obtain 9.9 g of trans-4-n-propylcyclohexanecarboxylic acid ethyl ester.

(I[) Lithium aluminum hydride 0.73g (1
9.1 mmof) was added to 30 ml of dry ether and heated under reflux for 1 hour. After cooling to about 10°C in an ice water bath, trans-4 dissolved in 30 mf of dry ether was added.
-n-Propylcyclohexanecarboxylic acid ethyl ester 5g (25.5mm) was gradually added dropwise. After the dropwise addition was completed, the mixture was stirred at room temperature for 1 hour and further heated under reflux for 1 hour. This was treated with ethyl acetate and 6N hydrochloric acid aqueous solution. After that, it was poured into 200mj of ice water.

After extraction with isopropyl ether, the organic phase was extracted with water,
It was washed successively with an aqueous sodium hydroxide solution and water, and dried over magnesium sulfate. After distilling off the solvent, it was purified by silica gel column chromatography to obtain trans-4-n-
3.5 g of propylcyclohexylmethanol was obtained.

(■) 3.4 g (22,4 mmoji!) of trans-4-n-propylcyclohexylmethanol was dissolved in 20 ml of pyridine. Add 20m of pyridine to this! ! 5.3 g of p-toluenesulfonic acid chloride dissolved in water was added dropwise while cooling to below 5°C in an ice water bath. 1 at room temperature
After stirring for 0 hours, ice water 200m+1! injected into. 6
After making the mixture acidic with an aqueous N hydrochloric acid solution, the mixture was extracted with isopropyl ether. The organic phase was washed with water repeatedly until the washing liquid became neutral, and then dried with magnesium sulfate. The solvent was distilled off to obtain trans-4-n-propylcyclohexylmethyl-p-toluenesulfonate.

(rV) Dimethylformamide 40 m I! 5-decyl 2-(4'-hydroxyphenyl)pyrimidine6.
3 g (20.2 mmof) was dissolved. To this was added 1.5 g of 85% potassium hydroxide, and the mixture was stirred at 100° C. for 1 hour.

6.9 g of trans-4-n-propylcyclohexylmethyl-p-toluenesulfonate was added to this, and the mixture was further stirred at 100°C for 4 hours. After the reaction is complete, pour it into ice water 2
00mj! and extracted with benzene.

After washing the organic phase with water, it was dried with magnesium sulfate. After distilling off the solvent, the residue was purified by silica gel column chromatography, and further recrystallized from a mixed solvent of ethanol/ethyl acetate to obtain the above-mentioned Exemplified Compound No. 1-4.

IR (cm-'): 2920.2840, 1608, 15841428.1
258,1164,800 Phase transition temperature (℃) 62.9 86.8 97
．． 8 136.8 (Sm2 is a smectic phase other than SmA or SmC, unidentified) An example of a specific structural formula of the compound represented by the general formula (n) is shown below.

The compound represented by the general formula (n) is disclosed in, for example, JP-A No. 6
1-93170. JP-A-61-24576, JP-A-61
-129170. Japanese Patent Publication No. 61-200972. Tokukai Showa 6
1-200973. Japanese Patent Publication No. 61-215372. It can be obtained by the synthesis method described in JP-A No. 61-291574.

For example, it can be obtained by the synthetic route shown below.

R 4 It can be obtained by mixing a seed, at least one kind of the compound represented by the general formula (II), and one or more other liquid crystal compounds in an appropriate ratio. The liquid crystal composition is preferably a ferroelectric liquid crystal composition, particularly a ferroelectric chiral smectic liquid crystal composition.

Specific examples of other liquid crystal compounds used in the present invention are listed below.

C101121o +cos +OCH2CHOC3H
7 Neriri υ Each of the liquid crystalline compounds represented by the general formula (I) and the liquid crystalline compound represented by the general formula (II) of the present invention, and one or more of the other liquid crystalline compounds mentioned above, or a ferroelectric compound containing them. The orientation ratio of each of the liquid crystal compounds represented by the general formula (1) and the general formula (II) of the present invention with respect to the liquid crystal composition (hereinafter abbreviated as ferroelectric liquid crystal material) per ioo parts by weight of the ferroelectric liquid crystal material is It is preferably 1 to 300 parts by weight, more preferably 5 to 100 parts by weight.

Furthermore, when using two or more of one or both of the liquid crystal compounds represented by the general formula (I) and general formula (TI) of the present invention, the blending ratio with the ferroelectric liquid crystal material is as described above. Per 100 parts by weight, 1 to 500 parts by weight, more preferably 10 to 100 parts by weight of a mixture of two or more of one or both of the liquid crystalline compounds represented by the general formula (I) and general formula (II) of the present invention. It is preferable to do so.

FIG. 1 is a schematic cross-sectional view of an example of a liquid crystal element having a ferroelectric liquid crystal layer according to the present invention, for explaining the structure of the ferroelectric liquid crystal element.

In FIG. 1, 1 is a ferroelectric liquid crystal layer, 2 is a glass substrate, 3 is a transparent electrode, 4 is an insulating alignment control layer, 5 is a spacer, 6 is a lead wire, 7 is a power source, 8 is a polarizing plate, 9 indicates a light source.

The two glass substrates 2 each have In2O3゜Sn0.
2 or ITO (Indium-Tin Oxid
A transparent electrode made of a thin film such as e) is coated. On top of this, a thin film of a polymer such as polyimide is rubbed with gauze or acetate flocked cloth to form an insulating alignment control layer that aligns the liquid crystals in the rubbing direction. Insulating materials such as silicon nitride, hydrogen-containing silicon carbide, silicon oxide, boron nitride, hydrogen-containing boron nitride, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, and fluoride An inorganic insulating layer such as magnesium is formed, and then polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyvaraxylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin , an organic insulating material such as melamine resin, Yulia resin, acrylic resin or photoresist resin as an orientation control layer.
The insulating alignment control layer may be formed of two layers, or may be a single layer of an insulating alignment control layer of an inorganic substance or an insulating alignment control layer of an organic substance. If this insulating alignment control layer is inorganic, it can be formed by a vapor deposition method, or if it is organic, it can be formed using a solution in which an organic insulating substance is dissolved or its precursor solution (solvent 0.1 to 20% by weight, preferably 0.5% by weight). 2~1O wt%)
It can be applied by a spinner coating method, dip coating method, screen printing method, spray coating method, roll coating method, etc., and cured and formed under predetermined curing conditions (for example, under heating).

The thickness of the insulating orientation control layer is usually 30 to 1 μm, preferably 30 to 3000, more preferably 50 to 1 μm.
000 people is suitable.

These two glass substrates 2 are kept at an arbitrary distance by a spacer 5. For example, using silica beads or alumina beads with a predetermined diameter as spacers, the glass substrate 2
There is a method in which the material is held between two sheets and the surrounding area is sealed using a sealing material such as an epoxy adhesive. In addition, a polymer film or glass fiber may be used as a spacer.

A ferroelectric liquid crystal is sealed between these two glass substrates.

The ferroelectric liquid crystal layer in which the ferroelectric liquid crystal is sealed is generally 0.5 to 20 μm, preferably 1 to 5 μm.

In addition, this ferroelectric liquid crystal has an SmC* phase (chiral smectic C phase) in a wide temperature range including room temperature (especially on the low temperature side), and when used as an element, it has a wide driving voltage margin and driving temperature margin. It is hoped that

In addition, in order to exhibit good homogeneous orientation and obtain a monodomain state especially when used as an element, the ferroelectric liquid crystal must be changed from the tomoyoshi phase to the ch phase (cholesteric phase) -3mA phase (smectic A phase) -SmC* Phase (chiral smectic C phase)
It is desirable to have the following phase transition series.

The transparent electrode 3 is connected to an external power source 7 by a lead wire.

Further, a polarizing plate 8 is bonded to the outside of the glass substrate 2.

The device shown in FIG. 1 is of a transparent type and is equipped with a light source 9.

FIG. 2 schematically depicts an example of a cell for explaining the operation of a ferroelectric liquid crystal element. 21a and 21b are In2O3, 5n02 or ITO (Indiu
A substrate (glass plate) coated with a transparent electrode made of a thin film such as m-Tin oxide), between which a liquid crystal molecular layer 22 is oriented perpendicular to the glass surface.
or SmH* phase liquid crystal is enclosed. A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 2
3 has a dipole moment (P soil) 24 in the direction perpendicular to its molecule. When a voltage equal to or higher than a certain threshold is applied between the electrodes on the substrates 21a and 21b, the helical structure of the liquid crystal molecules 23 is unraveled, and the dipole moment (P) 24 is all oriented in the direction of the electric field. The liquid crystal molecules 23 have an elongated shape and exhibit refractive index anisotropy in the long axis direction and the short axis direction.
Therefore, it is easily understood that, for example, if crossed Nicol polarizers are placed above and below a glass surface, a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of applied voltage can be obtained.

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, the helical structure of the liquid crystal molecules unravels even when no electric field is applied, as shown in Figure 3, and the dipole moment Pa or Pb is directed upward (34a) or downward (34b). ). In such a cell, an electric field Ea or Eb of different polarity above a certain threshold value is applied as shown in FIG.
is applied by the voltage applying means 31a and 31b, the dipole moment changes direction to upward direction 34a or downward direction 34b corresponding to the electric field vector of electric field Ea or Eb,
Accordingly, the liquid crystal molecules are aligned in either the first stable state 33a or the second stable state 33b.

As mentioned above, 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 with reference to FIG. 3, for example, when the electric field Ea is applied, the liquid crystal molecules are oriented in a first stable state 33a, and this state remains stable even when the electric field is turned off. Furthermore, when an electric field Eb in the opposite direction is applied, the liquid crystal molecules are oriented to the second stable state 33b and change their orientation, but they remain in this state even after the electric field is turned off. Also, the electric field E
As long as a or Eb does not exceed a certain threshold, the respective previous orientations are maintained.

When a simple matrix display device is constructed using a device in which a ferroelectric liquid crystal material having such characteristics is sandwiched between a pair of substrates,
For example, Japanese Unexamined Patent Publication No. 59-193426, No. 59-19
No. 3427, No. 60-156046 and No. 60
The driving method disclosed in Japanese Patent No.-156047 and the like can be applied.

FIG. 4 is a waveform diagram of the driving method used in the embodiment of the present invention. Further, FIG. 5 is a plan view of a ferroelectric liquid crystal panel 51 on which matrix electrodes used in the present invention are arranged. In the panel 51 of FIG. 5, a scanning line 52 and a data line 53 are wired to cross each other, and a ferroelectric liquid crystal is arranged between the scanning line 52 and the data line 53 at the intersection. .

In FIG. 4(A), Ss is the selection scanning waveform applied to the selected scanning line, SN is the unselected scanning waveform, and Is is the selection information waveform (black) applied to the selected data line. ), IN represents a non-selection information signal (white) applied to an unselected data line. Also, in the figure (I
s Ss) and (■, SS) are the voltage waveforms applied to the pixels on the selected scanning line, and the pixels to which the voltage (Is Ss) is applied display black, and the voltage (IN SS) is applied to the pixels on the selected scanning line.
) to which the pixel is applied assumes a white display state.

FIG. 4(B) is a time series waveform when the display shown in FIG. 6 is performed using the drive waveform shown in FIG. 4(A).

In the driving example shown in FIG. 4, the minimum application time Δt of the unipolar voltage applied to the pixels on the selected scanning line corresponds to the time of the write phase t2, the l line clear t, and the phase time 2. It is set to Δt.

Now, each parameter Vs, V of the drive waveform shown in FIG.
, , Δt is determined by the switching characteristics of the liquid crystal material used. FIG. 7 shows the change in transmittance T, that is, the V-T characteristic, when the actual driving voltage (Vs + V+) is changed while keeping the bias ratio constant, which will be described later. Here, Δt=50μS.

VX VXVs Bias stop valve / (-t = 10 cases) Fixed at -1/3. The positive side of Fig. 7 is shown in Fig. 4 (IN S
S), and a waveform shown as (rs Ss) is applied to the negative side.

Here, V, V3 are called actual drive threshold voltage and crosstalk voltage, respectively. However, v2<vl<v3) and △
V=(Va V+) is called a voltage margin and is a voltage width that allows matrix drive. It can be said that v3 generally exists in FLC matrix drive. in particular,
vB' in the waveform of Fig. 4 (A) (IN SS)
This is the voltage value that causes switching. Of course, it is possible to increase the value of RIv3 by increasing the bias ratio, but increasing the bias ratio means increasing the amplitude of the information signal, which may lead to an increase in flickering in terms of image quality. , which is undesirable because it causes a decrease in contrast. According to our study, a bias ratio of about 1/3 to 1/4 is practical. By the way, if the bias ratio is fixed, the voltage margin △V strongly depends on the switching characteristics of the liquid crystal material.
It goes without saying that a liquid crystal material with a large ΔV is very advantageous for matrix driving.

At a certain temperature like this, it is possible to write two states, "black" and "white", into a selected pixel depending on the two directions of the information signal, and non-selected pixels can write the "black" state into the selected pixel.
Or the upper and lower limits of the applied voltage that can maintain the "white" state and their widths (drive voltage margin △V)
is different and unique among liquid crystal materials. In addition, the drive margin decreases due to changes in the environmental temperature, so
In the case of an actual display device, it is necessary to set the drive voltage to the optimum value for the liquid crystal material and environmental temperature.

However, when the display area of such a matrix display device is expanded in practice, the difference in the environment in which the liquid crystal exists in each pixel (specifically, the difference in temperature and cell gap between electrodes) naturally increases. If a liquid crystal has a small drive voltage margin, it will not be possible to obtain a good image over the entire display area.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Example A liquid crystal composition 1-A was prepared by mixing the following parts by weight.

Exemplary compound no.

Structural formula %formula% Structural formula Weight part ■ Exemplary compound 1-l for this liquid crystal composition 1-A.

1-4 were mixed in the following weight parts, and liquid crystal Composition 1-B was obtained.

Exemplary compound no.

Structural Formula Next, optical responses were observed using cells prepared using these liquid crystal compositions according to the following procedure.

Prepare two 1.1 mm thick glass plates, form an ITO film on each glass plate, create a voltage application electrode,
Furthermore, StO2 was vapor-deposited on top of this to form an insulating layer.

On this substrate, a polyimide resin precursor [Toshi ■ 5P-51
0] 1.0% dimethylacetamide solution at 30 revolutions
Coating was performed for 15 seconds using a 0Or, p, m spinner. After the film was formed, a heating condensation firing process was performed at 300°C for 60 minutes.

The thickness of the coating film at this time was about 120 people.

This fired coating was rubbed with acetate flocked cloth, then washed with isopropyl alcohol solution, and silica beads with an average particle size of 1.5 μm were sprinkled on one glass plate. so that they are parallel to each other, and apply adhesive sealant [Rixon Bond (
Glass plates were glued together using Chisso@) and dried by heating at 100°C for 60 minutes to create a cell. The cell thickness of this cell was measured using a Bereck phase plate and was found to be approximately 1.5 μm.

A ferroelectric liquid crystal element was prepared by injecting the above-mentioned liquid crystal composition 1-B in an isotropic liquid state into this cell and slowly cooling it to 25°C at 20'C/h from the isokyoshi phase.

Using this ferroelectric liquid crystal element, the drive voltage margin △V with the drive waveform (l/3 bias) shown in FIG.
(V, -V2) was measured. The results are shown below. (In addition, △t is set to v2#15v) 10℃ 25°c4o0c (0.9 Drive voltage margin 11.0V Sohiro V
7V (setting at measurement △t) (310μ5
ec) (90μ5ec) (36μ5ec) Furthermore, if the voltage is set to the median value of the drive voltage margin at 25℃ and the measurement temperature is changed, the temperature difference that can be driven (
The driving temperature margin (hereinafter referred to as driving temperature margin) was ±3.2°C.

Also, the contrast during this drive at 25°C is lO
Met.

Comparative Example 1 Liquid crystal composition 1 in which only exemplary compound No. 1-1 was mixed with 1-A without mixing exemplary compound No. 2-4 of liquid crystal composition 1-H mixed in Example 1. Liquid crystal composition 1-D in which only exemplary compound No. 2-4 was mixed with 1-A without mixing -C and exemplary compound No. 1-1
It was created.

Instead of using liquid crystal compositions 1-B, liquid crystal composition 1-A,
All (
A ferroelectric liquid crystal element was produced in the same manner as in Example 1, and the driving voltage margin ΔV was measured. The results are shown below.

Drive voltage margin (setting △t during measurement) 10'C25°C40°C 1-A 8V 8V 6V
(400μ5ec) (110μ5ec) (
40μ5ec) 1-C8,5V 8. O.V.
6V (380μ5ec) (110μ5ec
) (40p 5ec)! -D9. O.V.
8.5V 6V (350J!Z 5e
e) (100p 5ec) (40μ5ec
) Furthermore, the driving temperature margin at 25°C is l-Ate+1.9°C, 1-Ct? ±2.2℃, 1-D upper 2゜4
It was °C.

As is clear from Example 1 and Comparative Example 1, the ferroelectric liquid crystal element containing the liquid crystal composition 1-B according to the present invention has a wider driving temperature margin, and is less sensitive to changes in environmental temperature and cell gap. It has an excellent ability to maintain a good image despite variations in the image quality.

Example 2 75 parts by weight of liquid crystal composition 1-A mixed in Example 1 were mixed with the following exemplified compounds in the following parts by weight to obtain liquid crystal composition 2-B.

A ferroelectric liquid crystal element was fabricated in the same manner as in Example 1 except that this was used, and the drive margin was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10℃ 25°0 40℃11.0
Wa, 0 Drive voltage margin 11. OV Reward■
V (setting at measurement △t) (300μ5ec)
(80 μ5 ec) (35 p 5 ec) Furthermore, the driving temperature margin at 25° C. was 3° to 4° C. above. Further, the contrast during this driving at this temperature was 11.

Comparative Example 2 Liquid crystal composition 1 in which only exemplary compound No. 1-17 was mixed with 1-A without mixing exemplary compound No. 2-43 of liquid crystal composition 2-B mixed in Example 2. -C
Liquid crystal composition 2-D was prepared by mixing only exemplified compound No. 2-43 with respect to 1-A without mixing exemplified compound No. 1-17.

Instead of using liquid crystal composition 1-B, liquid crystal composition 1-A,
A ferroelectric liquid crystal device was prepared in the same manner as in Example 1, except that 2-C and 2-D were injected into the cell, and the driving voltage margin ΔV was measured.The results are shown below. .

Drive voltage margin (setting △t during measurement) 10°0 25℃ 40℃1-A
8V 8V 6V (400μ5e
c) (110μ5ec) (40μ5ec)
2-C8,5V 8.5V 6V (
360μ5ec) (100p 5ec) (
40μ5ec) 2-D 9.5V 9.
OV 6V (300p 5ec) (9
0μ5ec) (40μ5ec) Furthermore, the driving temperature margin at 25°C is 1°9°C above at 1-A, 2-C
It was ±2.3°C at 2-D, and 2.5°C above at 2-D.

As is clear from Example 2 and Comparative Example 2, the driving temperature margin of the ferroelectric liquid crystal element containing the liquid crystal composition 2-B according to the present invention is wider, and it is less susceptible to changes in environmental temperature and cell gap. It has an excellent ability to maintain good image quality against variations.

Example 3 A liquid crystal composition 3-A was prepared by mixing the following parts by weight.

Exemplary compound no.

Structural formula Exemplary compounds 1-1 and 2 for this liquid crystal composition 3-A
-4.2-16 were mixed in the following parts by weight to obtain liquid crystal composition 3-B.

Exemplary compound no.

A ferroelectric liquid crystal element was prepared in the same manner as in Example 1 except that structural formula liquid crystal composition 1-B was replaced with this liquid crystal composition $-B.
The driving voltage margin ΔV was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10'C25℃ 40℃ Drive voltage? -') N 12.5V
12. OV 8.5V (setting △t during measurement)
(960μ5ec) (290/Z 5ee)
(90μ5ec) Furthermore, the driving temperature margin at 25°C was ±3.4°C. Also, at this temperature,
The contrast during this drive was 10.

Comparative Example 3 Of the liquid crystal composition 3-B mixed in Example 3, only exemplified compound No. 1-1 was mixed with 3-A without mixing exemplified compound No. 2-4.2-16. Liquid crystal composition 3-
Liquid crystal composition 3-D was prepared by mixing only exemplary compound No. 2-4.2-16 with 3-A without mixing C and exemplary compound No. 1-1.

Instead of using liquid crystal composition 1-B, liquid crystal composition 3-A,
A ferroelectric liquid crystal device was prepared in the same manner as in Example 1, except that 3-C and 3-D were injected into the cell, and the driving voltage margin △■ was measured.The results are shown below. .

Drive voltage margin (setting △t during measurement) 10℃ 25℃ 40℃ 3-A IOV IOV 8V
(1300μ5ec) (340μ5ec) (
100μ5ec) 3-C11, OV 10.5
V 8V (1000μ5ec) (320μ
5ec) (100μ5ec) 3-D I2
．． OV 10.5V 8V (980μ
5ec) (320μ5ec) (100p
5ec) Furthermore, the driving temperature margin at 25℃ is 3
-A ±2.4°C, 3-C ±2.6°C, 3-D ±2.4°C
The temperature was 2.8°C.

As is clear from Example 3 and Comparative Example 3, the ferroelectric liquid crystal element containing the liquid crystal composition 3-B according to the present invention has a wider driving margin, and is less susceptible to changes in environmental temperature and variations in cell gap. On the other hand, it has an excellent ability to maintain good images.

Example 4 75 parts by weight of liquid crystal composition 3-A mixed in Example 3 were mixed with the following exemplified compounds in the following parts by weight to obtain liquid crystal composition 4-B.

Exemplary Compound Magnetic Structure Formula A ferroelectric liquid crystal device was prepared in the same manner as in Example 1 except that this was used, and the drive margin was measured in the same manner as in Example 1 and the switching state etc. were observed. The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10℃ 25℃ 40℃ Drive voltage margin 13.5V 12.5V 9. O
V (Measurement setting △t) (940p 5ee)
(280p 5ec) (80p 5ec) 2 more
The driving temperature margin at 5°C was ±3.6°C. Further, the contrast during this driving at this temperature was 11.

Comparative Example 4 Of the liquid crystal composition 4-B mixed in Example 4, only exemplary compound No. 1-24 was mixed with 3-A without mixing exemplary compound No. 2-56.2-43. Liquid crystal composition 4
Liquid crystal composition 4-D was prepared by mixing only exemplified compounds Nos. 2-56 and 2-43 with 3-A without mixing -C and exemplified compounds Nos. 1-24.

Liquid crystal composition] Instead of using liquid crystal composition 3-B,
A ferroelectric liquid crystal device was prepared in the same manner as in Example 1 except that 4-C and 4-D were injected into the cell, and the driving voltage margin ΔV was measured. The results are shown below.

Drive voltage margin (measurement setting △t) 10℃ 25℃ 40℃3-A
IOV IOV 8V (1300
μ5ec) (340μ5ec) (100p
5ec) 4-CI 1.5V 10.5V
8V (1000μ5ec) (310μ5
ec) (100p 5ec) 4-D 11
．． OV 10. OV 8V (1100
ILsec) (320μ5ec) (100
μ5ec) Furthermore, the driving temperature margin at 25℃ is
±2.4℃ for 3-A, ±2.8℃ for 4-C, ±2.4℃ for 4-D
The temperature was 2.6°C.

As is clear from Example 4 and Comparative Example 4, the present invention has an excellent ability to maintain good images against temperature changes and cell gap variations.

Example 5 Liquid crystal composition 5 mixed in the following parts by weight did.

Create A Exemplary compound no.

Structural formula % Formula % Exemplary compound i -1,2 for this liquid crystal composition 5-A
-4 in the following parts by weight, respectively, to form a liquid crystal composition 5-4.
I got a B.

-A A ferroelectric liquid crystal element was prepared in the same manner as in Example 1 except that liquid crystal composition 1-B was replaced with this liquid crystal composition 5-B,
The driving voltage margin ΔV was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

(Measurement setting △t) (s20μ5ec) (2
20μ5ec) (72μ5ec) Furthermore, the driving temperature margin at 25°C was ±3.2°C. Further, the contrast during this drive at this temperature was lO.

Comparative Example 5 Liquid crystal composition 5 in which only exemplary compound No. 1-5 was mixed with 5-A without mixing exemplary compound No. 2-4 of liquid crystal composition 5-B mixed in Example 5. Liquid crystal composition 5-D in which only exemplary compound No. 2-4 was mixed with 5-A without mixing -C and exemplary compound No. 1-5
It was created.

Instead of using liquid crystal composition 1-B, liquid crystal composition 5-A,
A ferroelectric liquid crystal device was prepared in the same manner as in Example 1 except that 5-C and 5-D were injected into the cell, and the driving voltage margin ΔV was measured. The results are shown below.

Drive voltage margin (setting △t during measurement) 10℃ 25°0 40℃5-A
9V 9.5V 8.5V (1050
μ5ec) (280μ5ec) (78μ5e
c) 5-CIo,OV lO,OV
8.5V (920μ5ec) (260μ5ec)
(78μ5ec) 5-D Io, 5V
lo, OV 8.5V (900p 5e
c) (260μ5ec) (78p 5ec
) Furthermore, the driving temperature margin at 25°C is ±2.2°C for 5-A, ±2.3°C for 5-C, and ±2.5°C for 5-D.
Met.

As is clear from Example 5 and Comparative Example 5, the ferroelectric liquid crystal element containing the liquid crystal composition 5-B according to the present invention has a wider driving margin, and is less susceptible to changes in environmental temperature and variations in cell gap. On the other hand, it has an excellent ability to maintain good images.

Example 6 75 parts by weight of liquid crystal composition 5-A mixed in Example 5 were mixed with the following exemplified compounds in the following parts by weight to obtain liquid crystal composition 6-B.

A ferroelectric liquid crystal element was fabricated in the same manner as in Example 1 except that this was used, and the drive margin was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10℃ 25℃ 40℃13.0 Drive voltage margin 12. OV Kikan N'9. O
V (Measurement setting △t) (800μ5ec) (
(210μ5ec) (72μ5ec) Furthermore, the driving temperature margin at 25°C was ±3.6°C. Further, the contrast during this driving at this temperature was 11.

Comparative Example 6 Liquid crystal composition 6 in which only exemplary compound No. 1.1-3 was mixed with 5-A without mixing exemplary compound No. 2-43 of liquid crystal composition 6-B mixed in Example 6. Liquid crystal composition 6 in which only exemplary compound No. 2-43 was mixed with 5-A without mixing -C and exemplary compound No. 1-3
-D was created.

Instead of using liquid crystal composition 1-B, liquid crystal composition 5-A,
A ferroelectric liquid crystal element was prepared in the same manner as in Example 1, except that 5-C and 5-D were injected into the cell, and the driving voltage margin ΔV was measured.The results are shown below. .

Drive voltage margin (setting △t during measurement) 10℃ 25℃40℃ 5-A 9V 9.5V 8.
5V (1050μ5ec) (280p 5ec)
(78μ5ec)6-C9,5V 10.
OV 8.5V (960μ5ec) (2
60p 5ec) (78μ5ec) 6-D
Io, 5V 10,5V 8.5V (
900μ5ec) (240μ5ec) (7
Furthermore, the driving temperature margin at 25°C was ±2.2°C for 5-A, ±2.4°C for 6-C, and 2°8°C for 6-D.

As is clear from Example 6 and Comparative Example 6, the ferroelectric liquid crystal element containing the liquid crystal composition 6-B according to the present invention has a wider driving margin and is less susceptible to changes in environmental temperature and variations in cell gap. It has an excellent ability to maintain good image quality.

Example 7 Liquid crystal composition 1-A used in Example 1 and Comparative Example 1.

All of 1-B, 1-C, and 1-D were prepared in the same manner as in Example 1, except that the alignment control layer was made only of polyimide resin without using 5i02. The driving voltage margin was measured in the same manner as in Example 1. The results are shown below.

Drive voltage margin (setting △t during measurement) lOoC25°C40°C 4° (260μ5ec) (32μ5ec)
(+#μ5ec) (360μ5ec) (10
0μ5ec) (Poem μ5ec) 10, OV 9, Ov 6.5v D -μ5ec) (100μ5ec) 0 reference μ5ec) Furthermore, the driving temperature margin at 25°C is 3.2 1-B Shiku 2°C 2.2 1- The temperature was 2.0 1-A+t; 2°C.

As is clear from Example 7, even when the device configuration is changed, the device containing the ferroelectric liquid crystal composition 1-B according to the present invention has the same performance as in Example 1 compared to the device containing other liquid crystal compositions. The drive margin is wide, and the ability to maintain good images despite changes in environmental temperature and variations in cell gap is excellent.

Examples 8 to 15 In place of the exemplified compounds and liquid crystal compositions used in Example 1.3.5, the exemplified compounds and liquid crystal compositions shown in Table 1 were used in respective parts by weight to produce 8-B -15-B. A liquid crystalline composition was obtained. A ferroelectric liquid crystal device was fabricated using the same method as in Example 1, and the driving temperature margin at 25°C was measured in the same manner as in Example 1, and the switching state, etc., was observed. did.

Uniform alignment within each liquid crystal element created was good;
A monodomain state was obtained.

The measurement results are shown in Table 1.

As is clear from Examples 8 to 15, the ferroelectric liquid crystal elements containing liquid crystal compositions 8-B to 15-B according to the present invention have a wide driving margin and are resistant to changes in environmental temperature and variations in cell gap. It has an excellent ability to maintain good image quality.

〔Effect of the invention〕

The device containing the ferroelectric liquid crystal composition of the present invention has good switching characteristics, a large drive voltage margin, and a drive that allows all pixels to be satisfactorily driven in matrix even if there is a certain degree of temperature variation over the display area of the device. A liquid crystal element with a wide temperature margin can be obtained.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of an example of a liquid crystal display element using ferroelectric liquid crystal, and Figures 2 and 3 schematically represent an example of an element cell to explain the operation of a ferroelectric liquid crystal element. A perspective view, FIG. 4 is a waveform diagram of the driving method used in the examples, FIG. 5 is a plan view of a ferroelectric liquid crystal panel in which matrix electrodes are arranged, and FIG. 6 is a diagram showing the case shown in FIG. 4 (B). FIG. 7 is a schematic diagram of the display pattern when actual driving is performed using the serial drive waveform, and shows the change in transmittance when the driving voltage is changed, that is, V-
T characteristic diagram, Fig. 1 Ferroelectric liquid crystal layer Glass substrate Transparent electrode Insulating alignment control layer Spacer Lead wire Power source Polarizing plate Light source Incident light Transmitted light In Fig. 2, 1a 1b In Fig. 3, 1a Substrate Substrate strength Dielectric liquid crystal layer Liquid crystal molecule dipole moment (P soil) Voltage application means 1b 33a 3b 4a 4b a b Voltage application means First stable state Second stable state Upward dipole moment Downward dipole moment Upward electric field Downward The electric field of S,, J. Proceeding in a formal manner (spontaneous) January 9, 1988

Claims (2)

[Claims] (1) The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) However, R_1 is a linear or branched alkyl group that may have a substituent of C_1 to C_1_8, R_2 is C
_1 to C_1_2 linear alkyl group, There are ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼ At least one of the compounds represented by and the following general formula (II) It is a linear or branched alkyl group that may be present. However, at least one of them is optically active. X_2, X_
3 is a single bond, -O-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼At least one of the compounds shown
A ferroelectric chiral smectic liquid crystal composition characterized by containing seeds. (2) The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) However, R_1 is a linear or branched alkyl group that may have a substituent of C_1 to C_1_8, R_2 is C
_1 to C_1_2 linear alkyl group, There are ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼ At least one of the compounds represented by and the following general formula (II) It is a linear or branched alkyl group that may be present. However, at least one of them is optically active. X_2, X_
3 is a single bond, -O-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼At least one of the compounds shown
1. A liquid crystal element comprising a ferroelectric chiral smectic liquid crystal composition containing a seed and disposed between a pair of electrode substrates.