JPH03152186A - Ferroelectric liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having high-speed response even with relatively small spontaneous polarization value, showing Sc* phase in a wide temperature range, containing specific four kinds of optically active compounds in a specific ratio. CONSTITUTION:The objective composition containing (A) 76-95wt.% compound showing smectic C phase shown by formula I and/or formula II (R<1> and R<2> are 1-18C alkyl; R<3> and R<4> are 1-18C alkyl or alkoxy), (B) 2-10wt.% optically active compound shown by formula III (R<5> is 1-18C alkyl or alkoxy; X is group shown by formula IV or formula V; Y is H or halogen; * is asymmetric carbon atom), (C) 1-5wt.% one or more optically active compounds among compounds shown by formula VI to formula IX (R<6> and R<8> are 1-18C alkyl or alkoxy; R<7> and R<9> are 2-18C alkyl or 1-18C alkoxy) and (D) 2-8wt.% optically active compound shown by formula X (R<10> is 1-18C alkyl or alkoxy; Z is H or halogen).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to ferroelectric liquid crystal materials. More specifically, the present invention relates to a ferroelectric liquid crystal composition that is composed of a smectic liquid crystal compound and an optically active compound, and has a spontaneous polarization value of 20 H (:'cR4 or less) and yet has high-speed response, and an optical switching element using the same. .

[Conventional technology]

Liquid crystal compounds are widely used as materials for display elements, but most of these liquid crystal display elements are of the TN type display system, and the liquid crystal material used is one belonging to the nematic phase.

TN type display devices are light-receiving type, so while they have the characteristics of not tiring the eyes and extremely low power consumption, they also have slow response times.
The disadvantage is that the display cannot be seen depending on the viewing angle.

Recently, this method has been shifting toward making use of its characteristics as a flat display, and requires high-speed response and a wide viewing angle.

In order to meet these demands, attempts have been made to improve liquid crystal materials. However, compared to other light-emitting displays (e.g. EVA electroluminescent displays, etc.), T
In the N display method, a considerable difference is recognized in terms of response time and wide viewing angle.

It is essential to develop a new liquid crystal display system to replace the TN display system in order to take advantage of the characteristics of liquid crystal display elements, such as light-receiving type and low power consumption, and to ensure responsiveness suitable for light-emitting displays.

One such attempt was a display method using the optical switching phenomenon of a strong electrostatic liquid crystal, developed by N.A. Clark and 8. T
, proposed by Ragawal.

(Applied Physics Letters Appl.

Phys, Lett, 36.899, l 9
80)) Strongly galvanic liquid crystals were introduced in 1975 by K.R.B.
Its existence was first announced by Meyer et al.
36.69.19 flow) From the liquid crystal structure, chiral smectic C phase, chiral smectic F phase, chiral smectic F phase, chiral smectic G phase, and chiral smectic H phase (hereinafter SO*, 8P*,
They are abbreviated as SX*, SG* and 8H* phases. ) K belongs.

In the chiral smectic phase, the molecules form a layer, the molecules are tilted with respect to the plane of the layer, and the helical axis is perpendicular to the plane of the layer.

In the chi2rusmectic phase, spontaneous polarization occurs, so when a direct current electric field is applied parallel to this layer, the molecules reverse around the helical axis as the rotation axis depending on the polarity. Display elements using strongly galvanic liquid crystals utilize this switching phenomenon.

Among the cyclismectic phases, the 80* phase is currently attracting particular attention.

There are two possible display methods that utilize the so* phase switching phenomenon. One method is a birefringent type that uses two polarizers, and the other method is a guest-host type that uses a dichroic dye.

The characteristics of this display method are: (1) Response time is very fast.

(2) Has memory properties.

(3) Low viewing angle dependence.

It has the potential for high-density display, and is very attractive as an emergency button as a display element. However, even with this display method, there are currently many problems that must be solved.

Particularly recent problems have been the correlation between the magnitude of the spontaneous polarization value and the memorability, and the correlation between the magnitude of the spontaneous polarization value and switching of the SC* phase.

When a ferroelectric liquid crystal material with a spontaneous polarization value of 20n (to) 4 or more is injected into a cell with an insulating layer, the memory property disappears, making time-division driving impossible.
9! A problem is occurring.

This abnormal behavior is caused by an electric field (polarization field or ionic field) generated inside the cell in the direction opposite to the dipole direction of the liquid crystal molecules in ferroelectric liquid crystal materials with a spontaneous polarization value of 20n-2 or more. It has been reported that switching by applying a pulse voltage becomes impossible because the reverse voltage that appears becomes larger than the threshold voltage (for example, Masashi Ishikawa et al.: 14th Liquid Crystal Symposium, p. 100-1ol). 19
8B) Alternatively, J. Dijonet al.

: BID 88 DIGES'r p, 24
6-249 (1988)).

Generally, when a polyimide group is used as an insulator layer,
In order to avoid the above abnormal behavior, the spontaneous polarization value of the ferroelectric liquid crystal material should be 20nC14 or less, preferably l5
It is also said that nCaR must be below 4. In addition, when used in a 640 x 400 line display element, the following are particularly required: (1) It exhibits a %SC* phase in a wide temperature range including room temperature (2) It has a fast response time ( 150 μsec or less) (3
) Good orientation. Currently, the spontaneous polarization value is 20 HQCII
- or less, and a ferroelectric liquid crystal material (liquid crystal composition) that satisfies all of the above conditions has hardly been obtained.

For example, in Japanese Patent Application Laid-open No. 61-291679 and PCT International Publication No. WO36106401 pamphlet, So
A ferroelectric liquid crystal composition is shown in which a non-chiral 5-alkyl-2-(4-alkoxyphenyl)pyrimidine having a phase is mixed with an optically active compound, and the spontaneous polarization value is also 2.
It is described that it is 0nQcIL4 or less and exhibits an SC* phase in a wide temperature range including room temperature.

The former also shows that since the pyrimidine derivative has a very low viscosity, when used as a base SO mixture in a ferroelectric liquid crystal composition, the response time of an optical switching device can be shortened.

In addition, %Kokai No. 61-291679 discloses 5-alkyl-2-(4'-alkylbiphenyl-4)pyrimidine and 6-alkyl-2-(4-alkoxyphenyl)pyrimidine and its optically active It has been shown that a ferroelectric liquid crystal material made of a compound also exhibits an SC* phase in a wide temperature range BK including room temperature, and is also effective in improving responsiveness.

However, JP-A No. 61-2916 No. 9 and P.
The ferroelectric liquid crystal composition described in CT International Publication No. WO36106401 pamphlet has a large spontaneous polarization value and 8c
*The phase temperature range meets the above requirements, but the response time is still slow ((300-600 μ5ec)
, it is difficult to say that it is practical, and further improvement of responsiveness is desired.

Also, 4I! F Aisho 63-3 or 2'IQ number has SO
A non-chiral pyrimidine compound having a phase and the present invention (y
-2) A ferroelectric liquid crystal composition consisting of an optically active compound represented by the formula is shown, and it exhibits an SC* phase in a wide temperature range including room temperature, and also exhibits an extremely fast response. Are listed. For example, the ferroelectric liquid crystal composition described in Example 5 exhibits an SC* phase in a wide range of 6 to 62°C, has a response time of 100 μsec, and satisfies the above requirements, and has the above-mentioned characteristics. It seems to be very practical compared to the ferroelectric liquid crystal compositions described in JP-A No. 61-291619 or the pamphlet of PCT International Publication WOE 6106401.

However, Tokuran Show 63. -30 (The ferroelectric liquid crystal composition described in the specification of No. 2 Snow No. 9 also has a major problem when put into practical use. Namely, it does not have a cholesteric phase and is currently used in TN liquid crystal materials. The current orientation technology does not provide uniform orientation.

Currently, three methods are being tried for aligning ferroelectric liquid crystal materials: a shearing method, a temperature gradient method, and a surface treatment method. The shearing method involves applying shear stress to the smectic phase to orient it, and the temperature gradient method is similar to the epitaxial crystal growth method, which focuses on the fact that the smectic phase can be regarded as a one-dimensional crystal. The surface treatment method is practically used to align TN liquid crystal materials, and is a method in which a polymer film such as a polyimide film is coated on a cell substrate, and the surface is subjected to a 2-ping treatment to align liquid crystal molecules.

From the viewpoint of industrial production of liquid crystal display elements, it is desirable to orient liquid crystal molecules by a surface treatment method.

There are the following four types of phase transition types of ferroelectric liquid crystal materials. That is, a) Iso phase → 80* phase b) Iao phase → N* phase → SO* phase c) rso phase → 8^ phase → SO* phase and d) I
so phase→N* phase-+f31 phase→B(3*(here Xao
There are four types of phases: isotropic liquid phase, N* phase is cholesteric phase, and 8A phase is smectic phase.

Among these, those having the phase transition series shown in d) are those for which the current orientation technology (surface treatment method) can be used as is (see, for example, Japanese Patent Application Laid-Open No. 61-250086). Therefore, a ferroelectric liquid crystal material having the phase transition type shown in d) is highly desired.

Above (1)! 1IrFJ 1986-3 o 1 z@o
The ferroelectric liquid crystal compositions described in the specification do not have a cholesteric phase, and in order to uniformly align these compositions, a shearing method or a temperature gradient method must be used. k requires a long time and cannot be easily oriented. In addition, since the current alignment technology cannot be used as is, new equipment investment is required, and it is difficult to say that it is very practical.

As is clear from the above, the currently known ferroelectric liquid crystal materials cannot yet be said to be of practical use, and further improvement of their properties is desired.

[Problem to be solved by the invention]

As a result of our efforts to further improve the invention described in JP-A No. 61-291679, the inventors of the present invention have found that when the following compounds are combined, the spontaneous polarization value is 20.
n-' or less, and is SO in a wide temperature range including room temperature.
The inventors have discovered that it is possible to obtain a ferroelectric liquid crystal composition that exhibits *phase and has high-speed response, and has completed the present invention.

As is clear from the foregoing, the first object of the present invention is to have a spontaneous polarization value of 20 n0x-'' or less, exhibit a phase of 80' in a wide temperature range including room temperature, and The object of the present invention is to provide a ferroelectric liquid crystal composition that can be oriented and has a high-speed response.A second object is to provide an optical switching element that uses the above-mentioned liquid crystal composition and has an excellent response. There is a particular thing.

[Means to solve problems]

That is, the first aspect of the present invention is described in item (1) below. The aspects thereof will be described in sections (2) to (6) below.

(1) Consisting of four components A, B, C, and D described later, the content of each component is 76 to 95% by weight, 11% by weight, and B component is 2 to 10% by weight, based on the total amount of the four components. -A ferroelectric smectic C liquid crystal composition comprising 1 to 6% by weight of the 1C component and 2 to 8% by weight of the D component.

However, the A component is a general formula (in the formula, R1 and Hm are the same - each having 1 to 1B carbon atoms)
or different alkyl groups. ) or - formula (wherein Ha and R4 each have 1 to 18 carbon atoms)
or different alkyl or alkoxy groups.

) and has a smectic C phase, and the B component is - formula % formula %) ) (wherein Rs is an alkyl group having 1 to 18 carbon atoms) Base, Y
represents a hydrogen atom or a halogen atom, and * represents an asymmetric carbon atom. ), the component C is at least one compound selected from optically active compounds represented by any of the four general formulas described below, (in these formulas Re and R8 each independently represents an alkyl group or an alkoxy group having 1 to 18 carbon atoms.
By and R- each independently represent an alkyl group having 2 to 18 carbon atoms or an alkoxy group having 1 to 1 day carbon atoms, and * represents an asymmetric carbon atom. ), component C is represented by the general formula (wherein R1 represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group, 2 represents a hydrogen atom or a halogen atom, and * represents an asymmetric carbon atoms. ) is at least one compound selected from the optically active compounds represented by

(2) In the above paragraph (1), the human component is −Equation (3
) In the above item (1), component A is represented by the formula (wherein 11 represents a straight-chain alkyl group having 6 to 14 carbon atoms, and R1 represents a straight-chain alkyl group having 7 to 140 carbon atoms, respectively. )
or - formula (wherein R1 is a straight chain alkyl group having 6 to 18 carbon atoms,
Rt each represents a straight chain alkyl group having 7 to 18 carbon atoms. ) or - formula (wherein BS represents a straight-chain alkyl group having 4 to 18 carbon atoms; ) A ferroelectric smectic C liquid crystal composition, which is at least one compound selected from compounds represented by C and having a smectic C phase.

(In the formula, R"Gt represents a linear alkyl group having 4 to 14 carbon atoms; represents an xy group or an alkyl group having 5 to 5 carbon atoms, and R4 represents an alkyl group having 4 to 16 carbon atoms.) A ferroelectric smectic C liquid crystal composition, which is at least one compound selected from compounds having a smectic C phase and a smectic C phase.

(4) In claim (1), component B is represented by the general formula (wherein R8 represents a straight-chain alkyl group or alkoxy group having 4 to 12 carbon atoms, and .

) A ferroelectric smectic C liquid crystal composition, which is at least one compound selected from optically active compounds represented by:

(5) In the above item (1), the ferroelectric smectic C liquid crystal composition, wherein the C component is at least one compound selected from optically active compounds represented by any of the following four general formulas. .

(W-1a-1) (If-1b-1) (Tsu-2a-1) (In these two, R. and R$ each independently represent a straight-chain alkyl group or alkoxy group having 3 to 14 carbon atoms. (B? and R. each independently represent a straight-chain alkyl group or alkoxy group having 2 to 8 carbon atoms.) (6) In claim (1), component D is represented by the general formula (formula (wherein, R2O represents a straight-chain alkyl group or alkoxy group having 4 to 120 carbon atoms, and 2 represents one hydrogen atom, a fluorine atom, or a cyano group). A ferroelectric smectic C liquid crystal composition, which is a compound.

The second aspect of the present invention is ()) an optical switching element using the ferroelectric smectic C liquid crystal composition according to any one of items (1) to (6) above.

The present invention provides - A and B represented by formulas (1) to (V)
,C.

It is based on combining the excellent properties of component D compounds.

The excellent properties of each component will be explained in detail below.

In the present invention, the A component is - Formula 〇) and (1)
The compound represented by is a non-cyclic compound, but 8o
It has a very low viscosity, making it very useful as a component of one-based smectic phase compositions.

Regarding its usefulness, the present authors have already discovered it in Japanese Patent Application Laid-open No. 61
Although it is described in Japanese Patent No. 291679, it is also very effective as a component of the ferroelectric liquid crystal composition for the purpose of the present invention.

The bicyclic pyrimidine/compound which is component A of the present invention is preferably one in which R1 is a straight-chain alkyl group in the formula (2), and preferably has 6 to 18 carbon atoms, and has 6 to 18 carbon atoms.
-1.4 is more preferable. Formula 0) in which R1 is a linear alkyl group is suitable, and those having 7 to 18 carbon atoms are preferred, and those having 7 to 14 carbon atoms are more preferred.

As these bicyclic pyrimidine compounds, those of formula (I) in which the total number of carbon atoms of R1 and R3 is 14 to 20 are more preferable.

In addition, as the three types of pyrimidine/compounds, R
Preferably, a and R4 are linear alkyl groups or alkyl groups. Among these, those in which R1 is an alkoxy group having 4 to 18 carbon atoms or an alkyl group having 6 to 18 carbon atoms are preferable, and R1 is an alkoxy group having 4 to 14 carbon atoms or an alkyl group having 5 to 18 carbon atoms.
15 alkyl groups are more preferred. Moreover, those in which R4 is an alkyl group having 1 to 18 carbon atoms are preferred, and those in which R4 is an alkyl group having 4 to 15 carbon atoms are more preferred.

In general, compounds of formula (2) have a low clearing point and therefore have a
Many compounds have a phase in a low temperature range, and many of the compounds of formula (1) have a liquid crystal phase in a relatively high temperature range.

For example, in the formula (1) K, R1=C@H,, -R”
=C@H,! The phase transition temperature of the compound represented by - is Cr
26Sc No. 8A5B N65 Iao (here, N indicates a nematic phase) exhibits an SO phase in a relatively low temperature range, while - in the formula (mark), R''=C
The phase transition temperature of the compound represented by yHrs-1R'=CaHtt- is Cr58 80134 8A144 N
16F Iso, and exhibits an SO phase in a relatively high temperature range. Therefore, the compound represented by the formula (ri and the general formula (1)
By combining the compounds represented by k, a pace SO mixture having an SO phase over a wide temperature range from a low temperature range to a high temperature range can be obtained.

In the present invention, component A can be composed only of the compound of formula (r1) or only of the compound of formula (1). In this case, the empirical rules known to those skilled in the art can be used. A desired liquid crystal phase temperature range can be achieved by making use of The effect of lowering the eutectic point than K can be utilized.

When a compound of the formula (Iris) and a compound of the formula (1) are used in combination as component A, the preferred mixing ratio of both is, in terms of weight ratio, the compounds of the formula (I) 3 to the compounds of the formula (I) 1 to 9. be. A more preferable ratio between the two is 2:1 to 0.6:l.

In the present invention, component A plays a role as a base SO compound, so the concentration range of component A is A, B, and C.
It is desirable that the total amount of each component of D and D is 76 or more by weight.

The content of component A is 7 of the total amount of the four components AlB, C and D.
If the amount is less than 6% by weight, the SO* phase region of the composition obtained when a large amount of a compound poor in the chi2lsmectic C phase is mixed as other components may be significantly narrowed, or the spontaneous polarization of the obtained ferroelectric composition may be reduced. It is not preferable because the amount of component A may exceed 20 nCcR". Also, it is desirable that the content of component A is 95% by weight or less of the total amount of each component of A, B, C, and D. If it exceeds 96% by weight, the proportions of other components will decrease, and there is a concern that the helical pitch or the magnitude of spontaneous polarization in the SO* phase of the resulting composition cannot be set to a desired value.

Among the achiral compounds represented by the general formula (1) or (seal) that are component A of the present invention, the compounds shown in Tables 1 and 2 below are representative compounds that exhibit an SO phase. It is mentioned as.

Table 2 Table 2 (continued) Table 2 (continued) Table 2 (continued) As a non-chiral compound represented by the general formula is preferably one having an 80 phase. Even if it is a homologue compound of (!) or (seal) that does not exhibit an SO phase, the temperature range of the 80* phase of the obtained ferroelectric liquid crystal composition is not significantly reduced. It can be used as a component other than component A for the purpose of reducing viscosity or adjusting the SO* phase temperature range, as long as the amount is .

The optically active compound represented by the formula (1), which is the B component in the gA&C of the present invention, is a chi2yl compound that the present applicant previously applied for and has already been fully developed (for example, in JP-A-Sho). 6
1-43, JP-A No. 61-210056), it is a compound that exhibits an 80* phase in a high temperature range and also has a very large spontaneous polarization value.

For example, in the formula (m) VC, Rs=csH, o-
The degree is CrFlso* 9B N* 123
Iso, and the spontaneous polarization value is 110 n0J-(T-
(Tow-30℃) ■. Also, R-curvature IH17o-1xS-OC-1Y=
The phase transition temperature of the compound represented by -F is Cr 52 s
a*104 N*109 Iao, and the spontaneous polarization value is 132 n(Ex4(T-Tow-30℃)
It is.

This is because, in general, the response time (τ), spontaneous polarization value (Ps), and viscosity (η) of a ferroelectric liquid crystal composition do not cancel out the spontaneous polarization induced by the C component. The R-type compound, which is the enantiomer of the compound of formula (1), has P induced by the C component.
Since it acts in a direction that cancels out s, it is not suitable as a component of the present invention.

As the compound represented by formula (1), which is component B of the present invention, the following compounds whose absolute configuration with respect to the asymmetric carbon is S type can be mentioned as representative compounds.

There is a relationship. Therefore, a compound with low viscosity and a large spontaneous polarization value is desired.

The compound represented by the formula -, which is component B, is a compound having such characteristics, and in the ferroelectric liquid crystal composition of the present invention, the appearance of high-speed response and the SO* of the composition This compound plays an important role in increasing the maximum phase temperature.

The reasons for using an optically active liquid crystal whose absolute configuration with respect to asymmetric carbon is S type as component B are 1. C in the present invention described below
General formula (ff-1a) or rr-2b) which is a component
The compound represented by is a chiral compound and is a compound for which the present applicant has previously applied for a patent (% patent application No. 64-50, Japanese Patent Application Publication No. 63-26"763), and has spontaneous polarization. Since it is a compound with a very large value (approximately 300 nOm-), it plays an important role in producing high-speed response in the ferroelectric liquid crystal composition of the present invention (for example, Ra- In the case of C6H 0-, R'=i-OC,H, phase transition temperature: Cr ss so * 104
N*113 so, spontaneous polarization value: 3781000
cm+-1 (T-TO=-30°C)).

The optically active compound used as the C component is a compound in which the absolute configuration of the 2-substituted propoxy group at 2-C4C is S type. Even if this compound itself does not exhibit a liquid crystal phase, when it is mixed with the smectic C liquid crystal of formula 0), a large spontaneous polarization can be induced in the mixture. Since the direction of the spontaneous polarization induced by the C component has the same direction as the spontaneous polarization caused by the B component, the desired P8 can be achieved by adding a small amount of each of the B component and the C component.

The mixing ratio of the optically active compound of formula (m) as component B is:
The amount is preferably 2 to 10% by weight based on the total amount of each component A, B, C, and D. When an optically active compound represented by formula (ff-1a) or u-2b) is used as component C, the content thereof is suitably 1 to 5% by weight of the total amount of each component. If the content of component B or component C exceeds 10% by weight or 5% by weight, respectively, the resulting composition may increase in viscosity or its spontaneous polarization value may greatly exceed 20 noca4, which is undesirable.

Further, it is desirable that the total content of component B and component C is 14% by weight or less of the total amount of all components.

The spontaneous polarization value of the resulting composition is more desirably 15 n(
In order to obtain a value of g' or less, it is desirable that the total content of component B and component C does not exceed 13% by weight. If the content of component B or component C is less than 2 parts by weight or less than 1 part by weight, respectively, it is not preferable because a sufficiently large amount of Pg cannot be induced in the resulting composition.

The compound represented by the general formula (ff-1a) or y-2b) preferably has an SO* phase; ) is more compatible with the compound represented by K, and even if the compound itself does not have a BO* phase, it can be mixed with component A.
It exhibits an SO* phase over a wider temperature range, and also exhibits a large P8.

Therefore, even compounds that do not exhibit an SO* phase can be used in the ferroelectric liquid crystal composition of the present invention.

- Formula (W-1a) or + which is the C component of the present invention
As the compound represented by w-2b), the following compounds can be mentioned as representative compounds.

The compound represented by the general formula (Y), which is component C in the present invention, can be prepared, for example, according to the method described in JP-A-61-210056 or JP-A-63-233966. Although this compound is a chiral compound, its spontaneous polarization value is not very large, and in the present invention, it plays the role of adjusting the helical pitch. - In the compound represented by formula (V), the absolute configuration of the optically active site is S type, the twist direction of the helix in the SO* phase and N* phase is right, and the above-mentioned C component is the general formula ( IF-1a) or y-2b
) is opposite to the twist direction of the helix in the SO* phase or N* phase produced by the compound represented by. Therefore, the general formula (V
) By adding the compound represented by the formula K together with the C component, a strongly galvanic liquid crystal with a long helical pitch can be obtained.

The liquid crystal compound of the B component also has a force (hereinafter referred to as the swirling ability) that causes a spiral in the SO* phase or N* phase of the resulting mixture, similar to the C component and the compound of the C component. Since the swirling ability of the C component is not particularly large, it does not significantly affect the helical pitch in the 80* phase or N* phase of the composition of the present invention. The direction of the rotation ability of the B component is the same as that of the C component in the N* phase. The direction of the rotational ability of the B component compound in the So* phase is the same as the rotational ability of the C component for the compound CO- compound in which X is 8 in the formula (I), but for the compound in which X is 9 in the formula (II). is opposite to the OC-turning ability of the C component.

In addition, the direction of spontaneous polarization of the compound represented by - formula (V) is + type when the absolute configuration of the optically active site is S type, and (
However, in the formula (v) Itc, the direction of spontaneous polarization of the compound ZsiCN is type 1), -formula (*), (W
Although the direction of the spontaneous polarization of the compound represented by -1a) or W-2b) is opposite, the spontaneous polarization value of the compound represented by the formula (Vl) is very small (about 1nccR4), and the use Since the concentration is low, it does not have any adverse effect that would hinder the appearance of high-speed response in the ferroelectric liquid crystal composition that is the object of the present invention.It is a C component and is expressed by the formula (V). As the compound, the following compounds can be mentioned as typical compounds.

As a result of careful consideration, the ratio of each component in order to obtain a liquid crystal composition with excellent desired characteristics by taking advantage of the characteristics of each component A, B, C, and D as described above was determined as follows. What are the ingredients?
A preferable range is 6 to 96 weight - 1B component is 5 to 10 weight qb, C component is 1 to 5 weight 96, and C component is 2 to 8 weight.

As described above, in the present invention, an optically active compound having an S-type absolute configuration at the asymmetric center is used as the B component, and a 2-substituted p-poxy group is used as the C component, and the asymmetric center is 2. By using an optically active compound with an 8-type absolute configuration in -CGC, the directions of the spontaneous polarizations of both components are kept in the same direction. The object of the present invention can also be achieved by using, in place of component B and component C in the present invention, their enantiomers, optically active compounds whose absolute configuration at the asymmetric center is R type, respectively. is obvious. That is, the enantiomer of the optically active compound of component B is already the same, the direction of P8 is opposite to that of the compound of component B, and the enantiomer at the asymmetric center of the optically active compound of component C is as described above. It can be prepared by using an optically active compound of the 70-enantiomer as a raw material according to the method described in the bulletin of JP-A-64-50 and JP-A-63-26, No. 16. This is because it is certain that the direction of P8 expressed by the optically active compound is opposite to that of the C component compound.

〔Example〕

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

Various properties of the composition of the present invention were measured by the following methods.

The magnitude of spontaneous polarization (Ps) is measured at the Sawyer-Tauer dredge, and the polarity of the electric field is It was determined from the shift angle (corresponding to 2θ) of the extinction position under orthogonal Nicols when the is reversed.

The response time was determined by injecting each composition into an alignment-treated cell with an electrode spacing of 10 μm, and measuring a peak-to-peak voltage of 100 μm.
It was measured from the change in transmitted light intensity when a rectangular wave with a frequency of IKHz was applied.

The helical pitch (p) in SO*Saikai is approximately 20 mm in cell thickness.
It was determined by directly measuring the spacing of striped patterns (deN chiralization lines) corresponding to the helical pitch under a polarizing microscope using a cell with a homogeneous orientation of 0μ.

Examples 1 to 5 Table 3 shows the compositions of Examples 1 to 5 of the strongly castable liquid crystal compositions of the present invention, and Table 4 shows their characteristic values.

In addition, each composition in Table 3 means weight %. Table 4 Values at 5°C Example 6 The ferroelectric liquid crystal composition prepared in Example 1 was coated with polyimide as an alignment treatment agent, The liquid crystal cell was injected into a cell equipped with transparent electrodes with a cell gap of 2μ, whose surface had been subjected to parallel alignment treatment by rubbing, and this liquid crystal cell was sandwiched between two polarizers arranged in a crossed Nicol state. When a low frequency rectangular wave of 5Hz and 20% was applied, a clear switching operation with very good contrast (contrast ratio 1:15) was observed, and the response time was 80μaeC at 25℃, making it a liquid crystal with a very fast response. A display element was obtained.

3% by weight of anthraquinone dye D-16 (manufactured by BDI (manufactured by BDI)) was added to the ferroelectric liquid crystal composition prepared in Example F to make it a guest-host type. A composition was prepared. This composition was injected into a cell with a cell gap of 1 μm that had been treated in the same manner as in Example 6.
One polarizer was arranged so that the plane of polarization was parallel to the molecular axis, and the frequency was 0.5 Hz.

When a 40V low frequency alternating current was applied, a clear switching operation with very good contrast (contrast ratio 1:10) was observed, and the color liquid crystal display had an extremely fast response time of 130 μsec at 25°C. A device was obtained.

〔Effect of the invention〕

By combining liquid crystal compounds as in the present invention, it has a spontaneous polarization value of 2 On (:'ff' or less), has high-speed response, and has a strong So* phase in a wide temperature range including room temperature. A galvanic liquid crystal composition could be obtained.

Furthermore, the optical switching device using the liquid crystal composition of the present invention is a liquid crystal display device that exhibits a clear switching operation with very good contrast in both the birefringent display method and the guest-host display method, and has an extremely fast response. be.

Claims (7)

[Claims] (1) Consisting of four components A, B, C, and D described later, the content of each component is 76 to 95% by weight and component B is 2 to 10% by weight based on the total amount of the four components. %, the C component is 1 to 5% by weight, and the D component is 2 to 8% by weight. However, component A has the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, R^1 and R^2 each represent the same or different alkyl group having 1 to 18 carbon atoms.) or General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R^3 and R^4 each represent the same or different alkyl group or alkoxy group having 1 to 18 carbon atoms.) and at least one compound selected from compounds having a smectic C phase, and the B component has a general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (III) (In the formula, R^5 is carbon Represents an alkyl group or alkoxy group of numbers 1 to 18, X represents ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, Y represents a hydrogen atom or a halogen atom, * represents an asymmetric carbon atom), and the C component is at least one compound selected from optically active compounds represented by any of the four general formulas described below, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-1a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-1b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-2a) ▲Mathematical formulas, chemical formulas, There are tables, etc. ▼ (IV-2b) (In these formulas, R^6 and R^8 each independently represent an alkyl group or alkoxy group having 1 to 18 carbon atoms, and R^7 and R^8 each independently carbon number 2-18
represents an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and * represents an asymmetric carbon atom. ), D component has the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (V) (In the formula, R^1^0 represents an alkyl group or alkoxy group having 1 to 18 carbon atoms, and Z is a hydrogen atom or a halogen At least one compound selected from the optically active compounds represented by the following formulas (* represents an atom and * represents an asymmetric carbon atom). (2) At the top of claim No. (1), component A is a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -1) (In the formula, R^1 is a straight chain having 6 to 18 carbon atoms. , and R^2 represents a linear alkyl group having 7 to 18 carbon atoms, respectively.) Or the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (II-1) (In the formula, R^ 2 represents a straight-chain alkoxy group having 4 to 18 carbon atoms or a straight-chain alkyl group having 6 to 18 carbon atoms, and R^4
represents a straight-chain alkyl group having 4 to 18 carbon atoms. ) and having a smectic C phase. (3) In claim (1), the A component is
General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I-2) (In the formula, R^1 is a straight-chain alkyl group with 6 to 1 carbon atoms, and R2 is a straight-chain alkyl group with 7 to 14 carbon atoms. ) or general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (II-2) (In the formula, R^3 is a straight-chain alkoxy group having 4 to 14 carbon atoms or a straight chain alkoxy group having 6 to 16 carbon atoms. , and R^4 represents an alkyl group having 4 to 15 carbon atoms, and is at least one compound selected from compounds having a smectic C phase. C liquid crystal composition. (4) In claim (1), component B is a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III-1) (In the formula, R^5 is a straight chain having 4 to 12 carbon atoms. 1. A ferroelectric smectic C liquid crystal composition, which is at least one compound selected from optically active compounds represented by (1) representing an alkyl group or an alkoxy group, and X and Y having the above-mentioned meanings. (5) In claim (1), the ferroelectric smectic C liquid crystal is characterized in that the C component is at least one compound selected from optically active compounds represented by any of the following four general formulas. Composition. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-1a-1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-1b-1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-2a-1 ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV-2b-1) (In these formulas, R^6 and R^8 each independently represent a straight-chain alkyl group or alkoxy group having 3 to 14 carbon atoms. and R^7 and R^9 each independently have a carbon number of 2
-8 straight chain alkyl group or alkoxy group. ) (6) In claim (1), component D is a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (V-1) (In the formula, R^1^0 is a carbon number of 4 to 12 A ferroelectric smectic C liquid crystal, which is at least one compound selected from optically active compounds represented by (representing a straight-chain alkyl group or alkoxy group, and Z represents a hydrogen atom, a fluorine atom, or a cyano group) Composition. (7) An optical switching element using the ferroelectric smectic C liquid crystal composition according to any one of claims (1) to (6).