JPH0987625A - Liquid crystal element and liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chiral smectic liquid crystal element having a liquid crystal structure with a small tilting layer angle, and having a high speed, a high contrast, a large area, a high definition, a high luminance, a high reliability and a high endurance by providing electrodes, specific orientation regulating layers and a liquid crystal layer between its top and bottom preform plates. SOLUTION: This liquid crystal element has electrodes 3, orientation regulating layers 4 having <=200Å membrane thickness in at least one of them and a liquid crystal layer 1 between top and bottom preform plates 2, and also its liquid crystal layer 1 is constituted by a chiral smectic liquid crystal composition containing >=70wt.% of the group of liquid crystal compound (A) containing fluorine, having a (potential) smectic intermediate phase, and a fluorocarbon terminal part (A1 ) and a hydrocarbon terminal part (A2 ), where A1 and A2 are bound together at a central nucleus, >=30wt.% of compound (A') containing ethereal oxygen in its A1 chain within A based on the total amount of the composition, and a compound (B) capable of stably lowering the resistance of the liquid crystal layer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element used for a light valve used in a flat panel display, a projection display, a printer and the like, and a liquid crystal device using the same.

[0002]

2. Description of the Related Art A CRT is known as the most widely used display. CRT
Is widely used as a moving image output for televisions and VTRs, or as a monitor for personal computers. However,
Due to the characteristics of the CRT, the visibility of a still image may be reduced due to flicker or scanning fringes due to insufficient resolution, or the phosphor may be deteriorated due to burn-in. In addition, recently, it has been found that the electromagnetic waves generated by the CRT adversely affect the human body, which may impair the health of the VDT worker.
Further, because of the large volume behind the screen in terms of structure, space saving in offices and homes may be hindered, and it may not be possible to fulfill the responsibility as a display in an advanced information society.

As a solution to such a disadvantage of the CRT, there is a liquid crystal display element. For example, M. Shut (M.
Schadt) and W. Helfrich (W. He)
Lfrich) "Applied Physics Letters"
s ") Volume 18, Issue 4 (issued February 15, 1971)
Twisted shown on pages 127-128
A liquid crystal device using a nematic (twisted nematic) liquid crystal is known. One is a simple matrix type liquid crystal element, which has a cost advantage. This liquid crystal element has a problem that crosstalk occurs in time-division driving using a matrix electrode structure with a high pixel density, so that the number of pixels is limited. Moreover, since the response speed is as slow as several tens of milliseconds or more, its use as a display is limited. In recent years, a liquid crystal element called TFT has been developed for such a simple matrix type. Since this type creates a transistor in each pixel, the problems of crosstalk and response speed are solved, but it is industrially very difficult to create a liquid crystal element without a defective pixel as the area increases. Difficult and, if possible, at great cost.

In order to improve the drawbacks of the conventional liquid crystal device, the use of a bistable liquid crystal device is clarified by Clark and Lagerw.
all) proposed. (JP-A-56-107
216, U.S. Pat. No. 4,367,924) As the liquid crystal having the bistability, a ferroelectric liquid crystal having a chiral smectic C phase or a chiral smectic H phase is generally used. Since the ferroelectric liquid crystal performs inversion switching by spontaneous polarization, the ferroelectric liquid crystal has a very fast response speed and can exhibit a bistable state with memory properties. Further, since the viewing angle characteristics are also excellent, it is considered that they are suitable as a high-speed, high-definition, large-area display element or a light valve. Recently, Chandani and Takezoe have also proposed a chiral smectic antiferroelectric liquid crystal device having three stable states (Japanese Journal of Applied Physics).
of Applied Physics) 27, 198
8 years L729 page).

In such a chiral smectic liquid crystal device, when an ordinary rubbing-treated polyimide alignment film is used for alignment, an apparent tilt angle (an angle formed by two stable molecular axes is 1) is obtained. /
In 2), generally, the angle is at most 3 ° to 8 °, so that the transmittance was 3 to 5% and the contrast was around 10 which was a very low value. In addition, "Structure and Physical Properties of Ferroelectric Liquid Crystal"
(Corona Publishing Co., Ltd., Atsuo Fukuda, Hideo Takezoe, 1990), there is also a problem that a zigzag alignment defect occurs and the contrast is significantly lowered.
This defect is caused by the fact that the layered structure of the chiral smectic liquid crystal carried between the upper and lower substrates forms two types of chevron-like structures. Hanyu et al. Obtained a liquid crystal element with a large contrast by eliminating the zigzag defect by increasing the pretilt angle of the liquid crystal molecules at the interface of the alignment control film and increasing the apparent tilt angle (Japanese Patent Laid-Open No. HEI-3). No. 252624). However, even if the method of Hanyu et al. Is used, in order to obtain a good driving state, for example, the tilt angle must be 16 ° or less, and the tilt angle (22.5 °) at which the ideal transmittance can be obtained. ), There is room for further improvement.

On the other hand, recently, the chevron structure, which is the cause of the low contrast, has been eliminated, and a layered structure called a bookshelf (hereinafter referred to as a bookshelf) or a structure close to it has been developed to realize a high contrast. There is a movement (for example, "Next-generation liquid crystal displays and liquid crystal materials" edited by CMC Inc., Atsuo Fukuda 199
2 years). One method is to use a naphthalene-based liquid crystal material. In this case, the tilt angle is about 10 degrees, which is much smaller than the ideal maximum transmittance of 22.5 degrees and has a low transmittance. There is also a problem that the bookshelf structure does not reversibly appear with respect to temperature. Another typical example is a method of inducing a bookshelf structure by applying a high electric field from the outside to a liquid crystal element having a chevron structure, but this method also has instability against external stimuli such as temperature. It's a problem. These bookshelf types have just been discovered, and there are various other problems for practical use.

Furthermore, a liquid crystal compound having a perfluoroether side chain as a liquid crystal having a structure of a bookshelf or a structure close thereto (US Pat. No. 5,262,082, International application patent WO 93/22396, 1993 4th International Conference on Ferroelectric Liquid Crystals) P-46, Marc D. Radcliffe
Are disclosed. This liquid crystal can exhibit a bookshelf or a structure having a small layer inclination angle close to it without using an external field such as an electric field, and is suitable for a high-speed, high-definition, large-area liquid crystal element and a display device. However, further improvements are required in terms of speed, orientation, contrast, driving stability, etc. of liquid crystal elements. Moreover, in addition to improving each characteristic, a method and invention for improving a plurality of characteristics are required for higher performance.

[0008]

The present invention has been made in view of such a conventional technique. In fact, in a liquid crystal device using a conventional liquid crystal composition, spontaneous polarization (P
For liquid crystal compositions with large s), Yoshida et al. 142 (1987), a reverse electric field in the liquid crystal element may cause switching failure. For this reason, when these conventional liquid crystal elements are used as a display, when the user rewrites from black to white, "faint black" is visually recognized as an afterimage, and the display quality as the display deteriorates. Will end up. Therefore, by reducing the resistance of the liquid crystal composition, Yoshida et al. Relaxes the internal electric field induced by the switching of the ferroelectric liquid crystal molecules at an early stage,
Good bistability is obtained (Japanese Patent Application Laid-Open No. 4-211492).

However, a liquid crystal device using the liquid crystal composition used in the examples of JP-A-4-21192 is
As mentioned above, the low transmittance with a small apparent tilt angle,
It is a low contrast liquid crystal element. On the other hand, in the liquid crystal element described in the above-mentioned JP-A-3-252624, the present inventors examined a method similar to that of JP-A-4-21192.

That is, the liquid crystal composition used in JP-A-3-252624 is disclosed in JP-A-4-21149.
When a liquid crystal element was prepared by adding a compound that stably reduces the resistance described in JP-A No. 2-2, the orientation was disturbed and the bistability was lost.

Therefore, the present invention realizes a high-speed, high-contrast, large-area, high-definition, high-luminance, high-reliability and high-quality chiral smectic liquid crystal device having a bookshelf or a liquid crystal structure having a small layer tilt angle. However, it is intended to provide a liquid crystal device having high brightness and high contrast by using the liquid crystal element.

[0012]

As a result of intensive studies, the inventors of the present invention have at least electrodes and an orientation control layer on upper and lower substrates, and at least one of the orientation control layers has a film thickness of 200 Å.
In the following liquid crystal device, a liquid crystal device using a chiral smectic liquid crystal composition containing a substance (conductive dopant) that stably reduces the resistance of the liquid crystal layer as liquid crystal realizes very high-speed response and By expressing a structure with a small tilt angle of the shelf or a layer close to it, it is possible to realize a high-speed, high-contrast, large-area, high-definition, high-brightness chiral smectic liquid crystal element, with no or very reduced afterimage phenomenon. It has been found that it has good driving characteristics.

That is, according to the present invention, in a liquid crystal device having at least electrodes and an orientation control layer on upper and lower substrates, and at least one orientation control layer having a thickness of 200 Å or less, the liquid crystal has a fluorocarbon terminal portion and a hydrocarbon terminal portion. Including,
A liquid crystal composition containing 70% by weight or more of a fluorine-containing liquid crystal compound group having both smectic mesophases or a latent smectic mesophase, in which both end portions are bound by a central nucleus. A chiral smectic liquid crystal composition containing 30 wt% or more of a compound containing at least one ether oxygen in the chain in the fluorocarbon end chain in the total amount of the liquid crystal composition, and containing at least one substance that stably reduces the resistance of the liquid crystal layer. A liquid crystal element characterized by being an object, and a liquid crystal device using the liquid crystal element.

As used herein, a compound having a latent smectic mesophase means a compound having a smectic mesophase or a mixture with another compound having a latent smectic mesophase even if it does not show a smectic mesophase by itself. , A compound that develops a smectic mesophase under appropriate conditions. In the present invention, the ether oxygen in the chain refers to oxygen forming the main chain in the perfluoroether chain.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal composition used in the present invention comprises the above-mentioned fluorocarbon end portion and hydrocarbon end portion, both end portions being bound by a central nucleus, and a smectic mesophase or a latent smectic mesophase. Containing a liquid crystal compound group containing fluorine as a main component. In the present invention, in order to develop a bookshelf structure or a structure having a small layer inclination angle close thereto, the compound group is contained in an amount of 70% by weight or more.

The fluorocarbon end portion and the hydrocarbon end portion used in the liquid crystal composition of the present invention are contained, and both end portions are bound by a central nucleus, and have a smectic mesophase or a latent smectic mesophase. And a fluorine-containing liquid crystal compound (perfluoroether liquid crystal compound) containing at least one ether oxygen in the chain in the fluorocarbon terminal chain is disclosed in US Pat. No. 5,262,082 and International Patent Application WO 93/22.
396, 1993 4th International Conference on Ferroelectric Liquid Crystals P-46
(Marc D. Radcliffe et al.), The perfluoroether liquid crystal compound is preferably 30% by weight or more, and more preferably 50% by weight in order to reveal a structure having a small layer tilt angle close to a bookshelf. % Or more is contained.

In the present invention, preferably, a fluorine-containing liquid crystal containing the above-mentioned fluorocarbon end portion and hydrocarbon end portion, both end portions being bound by a central nucleus, and having a smectic mesophase or a latent smectic mesophase. The compound is -UC _w F _{2w + 1} or -V
_{(C x F 2x O) z} C y F 2y + 1 has a fluorocarbon terminal chains where represented by, and the fluorine-containing liquid crystal compounds comprising at least one chain ether oxygen in the fluorocarbon terminal chain, -V '(C _x' F _{2x '} O) _{z'C y'}
F _{2y '+ 1} having a fluorocarbon terminal chains containing a chain ether oxygen represented by [wherein x and x' are each (C _x F _2x O) and independently to _{(C x 'F 2x' O} ) 1 to 1
Is an integer from 0, y and y ′ are integers from 1 to 10, z and z ′ are integers from 1 to 10, and w is 1
It is an integer from 1 to 20. U is -CO-O- (CH
_{2) r -, - O- (} CH 2) r -, - (CH 2) r -, - OS
_{O 2 -, - SO 2 -} , - SO 2 (CH 2) r -, - O (C
_{H 2) r -O (CH 2} ) r '-, - (CH 2) r -N (C p H
_{2p + 1) -SO 2 -,} - (CH 2) r -N (C p H 2p + 1) -C
O-( '. Is an integer from 1 independently to 20, p is an integer from 0 to 4, V and V where r and r)' represents a single bond, -COO-C _r H _2r - , -O-C _r H
_{2r -, - O- (C s} H 2s O) t -C u H 2u -, - OSO
_{2 -, - SO 2 -,} - SO 2 -C r H 2r -, - C r H 2r -,
_{-C r H 2r -N (C p} H 2p + 1) -SO 2 -, - C r H 2r -N
(C _p H _{2p + 1} ) -CO- (where r and u are each independently an integer from 1 to 20, and s is each (C _s
H _2s O) is an integer from 1 to 10 independently, and t is 1
Is an integer from 0 to 6 and p is an integer from 0 to 4)].

More preferably, a fluorine-containing liquid crystal compound having the above-mentioned fluorocarbon end portion and hydrocarbon end portion, both end portions being bound by a central nucleus, and having a smectic mesophase or a latent smectic mesophase, The compound represented by formula I-1 or I-2, wherein the fluorine-containing liquid crystal compound containing at least one ether oxygen in the chain in the fluorocarbon terminal chain is a compound represented by the following general formula I-2. .

[General Formula I-1]

[0020]

Embedded image And a, b and c are each independently 0 or 1 to 3
Represents the integer. However, a + b + c is at least 2.

M ₁ and N ₁ are independently -COO-,
-COS -, - COSe -, - COTe -, - (CH 2
CH _{2) d} - _(d is an integer of from 1 4), - CH = C
H -, - CH = N - , - CH 2 -O -, - CO -, - O
-, Represents a single bond and may have any orientation.

X, Y and Z are substituents on B ₁ , D ₁ and E ₁ and are independently --H, --Cl, --F and --B.
_{r, -I, -OH, -OCH 3} , -CN, representing the -NO _2. l, m, and n each independently represent an integer of 0 to 4.

G ₁ is --COO--C _e H _2e- , _--O --C _e H
_{2e -, - C e H 2e} -, - OSOO -, - OOSO -, -
_{SOO -, - SOOC e H 2e} -, - OC e H 2e -OC e 'H
_{2e '-, - C e H} 2e -N (C p H 2p + 1) -SOO -, - C e
_{H 2e -N (C p H 2p} + 1) -CO- (e, e ' represents an integer of from independently 1 to 20, p represents. An integer from 1 to 4) represents a.

[0024] A ₁ is _{-O-C f H 2f -O-} C g H 2g + 1, -
_{C f H 2f -O-C g} H 2g + 1, -C f H 2f -R ', - O-C f
_{H 2f -R ', - COO-} C f H 2f -R', - OCO-C f
H _2f -R '(R' is _{-Cl, -F, -CF 3, -NO} 2,
_{-CN, -H, -COO-C f} 'H 2f' + 1, -OCO-C
_{f ′} H _{2f ′ + 1} , f, f ′, and g each independently represent an integer of 1 to 20. ), A ₁ may be linear or branched.

R is -C _x F _{2x + 1} and x is 1 to 20
Represents an integer up to. )

[General Formula I-2]

[0027]

Embedded image And a, b and c are each independently 0 or 1 to 3
Represents the integer. However, a + b + c is at least 2.

M and N are independently -COO-,-
COS -, - COSe -, - COTe -, - (CH 2 C
H ₂ ) _d- (d represents an integer of 1 to 4), -C≡C-,
-CH = CH -, - CH = N -, - CH 2 -O -, - C
It represents O-, -O-, or a single bond, and its orientation may be any.

Each of X, Y and Z is independently -H and -C.
l, -F, -Br, -I, -OH, -OCH 3, -C
H _3, represents -CF _3, -OCF _3, -CN, and -NO _2. Each of l, m, and n independently represents an integer of 0 to 4.

[0030] G is _{-COO-C e H 2e -,} - O-C e H 2e
_{-, - O (C e "} H 2e" O) t -C e 'H 2e' -, - C e H
_{2e -, - OSOO -, -} SOO -, - SOOC e H
_{2e -, - C e H 2e} -N (C p H 2p + 1) -SOO -, - C e
_{H 2e -N (C p H 2p} + 1) -CO- (e, e ' represents an integer of from 1 independently to 20, p is an integer from 0 to 4 .e "is respectively ( C _{e "} H _2e" O) independently represents an integer of 1 to 10, and t represents an integer of 1 to 6).

[0031] A is _{-O- (C f H 2f -O)} u -C
_{h H 2h + 1, - (} C f H 2f -O) u -C h H 2h + 1, -C f H 2f
_{-W, -O-C f H 2f} -W, -COO-C f H 2f -W, -
_{OCO-C f H 2f -W (} W is -Cl, -F, -CF _3, -
_{NO 2, -CN, -H, -COO} -C h H 2h + 1, -OCO
-C _h H _{2h + 1} , where f and h are independently 1 to 2
Represents an integer of 0. u is an integer of 1 to 10. ), A may be linear or branched.

[0032] R is _{- (C x 'F 2x'} O) z ' is a _{+ 1, x''C y} ' F 2y each of _{(C x 'F 2x' O} ) to from 1 independently until 10 It is an integer, y'is an integer from 1 to 10, and z'is an integer from 1 to 10. )

Further, specific structural examples of the perfluoroether liquid crystal compound include compounds having the following structures.

[0034]

Embedded image

[0035]

[Chemical 6]

[0036]

[Chemical 7]

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

Examples of the substance (conductive dopant) that is added to the liquid crystal composition used in the present invention to stably reduce the resistance of the liquid crystal layer are, for example, the following general formulas (1) to (4).
A compound represented by any of the above is used.

[0041]

Embedded image

(However, R is H or has 1 to 18 carbon atoms.
Represents a linear or branched alkyl group which may have a substituent. X is -O- or -COO-, -O
Indicates CO-. )

[0043]

[Chemical 12]

[0044]

Embedded image

In the general formula (1), R is preferably selected from the following i) and ii).

I) n-alkyl group having 1 to 18 carbon atoms, more preferably n-alkyl group having 4 to 14 carbon atoms

[0047]

Embedded image

(However, p is an integer of 0 to 7, and k is 1
Is an integer from 9 to 9. Further, when k is 2 or more, it may be optically active. )

Further, X preferably represents --O--.

Specific structural formulas of the compounds represented by the above general formula (1) are shown below.

[0051]

[Chemical 15]

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

The compound represented by the general formula (1) can be generally synthesized by the following route.

[0057]

Embedded image

Synthesis Example 1 Synthesis of 2,3-dicyano-4-hexyloxyphenol 27 g (168.8 m) of 2,3-dicyanohydroquinone
mol), 22.2 g of 85% potassium hydroxide (337 m
(mol) was dissolved in 65 ml of methanol and 302 mol of dimethylformamide, and the temperature was raised to 50 ° C. Hexyl bromide (33.4 g, 202.4 mmol) was added dropwise over 25 minutes, the temperature was raised to 100 ° C., and the mixture was stirred for 3 hours. After pouring into cold water and washing with ether, 6N hydrochloric acid was added to the aqueous layer to adjust the pH to 1. The precipitated crystals were extracted with ether, and the ether layer was washed with 5% aqueous sodium hydrogen carbonate solution and water. After distilling off the solvent, the crude crystals were treated with activated carbon and recrystallized from methanol to obtain 13.1 g of 2,3-dicyano-4-hexyloxyphenol.

In the compound represented by the general formula (2), R ₁ is preferably an n-alkyl group having 1 to 18 carbon atoms, and more preferably an n-alkyl group having 3 to 14 carbon atoms.

Examples of specific structural formulas of the compound represented by the general formula (2) are shown below.

[0061]

[Chemical 21]

[0062]

Embedded image

[0063]

Embedded image

Typical synthetic examples of the compound represented by the general formula (2) are shown below.

Synthesis Example 2 (Synthesis of Compound No. 2-20) (1) 4-n-pentylcyclohexanecarboxylic acid chloride dissolved in 12 ml of ether in a dispersion solution of 1.75 g of lithium aluminum hydride and 40 ml of dry ether. 10 g was added dropwise at a liquid temperature of 5 ° C or lower. After stirring overnight at room temperature, a 5% hydrochloric acid aqueous solution was added to adjust the pH to about 1, and the mixture was extracted with ether. The organic layer was washed successively with water, a 5% aqueous sodium hydroxide solution and water, and dried over anhydrous magnesium sulfate. After filtration, the solvent was distilled off to obtain 8.2 g of 4-n-pentylcyclohexylmethanol.

(2) 8.0 g of 4-n-pentylcyclohexylmethanol was dissolved in 8 ml of pyridine and 8 ml of toluene. To this, 6.0 g of methanesulfonic acid chloride
Was added dropwise at a liquid temperature of 10 ° C. or lower. After stirring overnight at room temperature, it was poured into cold water and extracted with toluene. 5% hydrochloric acid aqueous solution,
After sequentially washing with water, it was dried over anhydrous magnesium sulfate. After filtration, the solvent was distilled off and methanesulfonic acid 4-n-
11.3 g of pentylcyclohexylmethyl was obtained.

(3) To 15 ml of methanol and 60 ml of N, N-dimethylformamide were added 5.6 g of 2,3-dicyanohydroquinone and 4.6 g of 85% potassium hydroxide, and the mixture was heated to 50 ° C. and dissolved. To this, 11.0 g of 4-n-pentylcyclohexylmethyl methanesulfonate was added, and the mixture was stirred at 100 ° C for 3 hours. This was poured into cold water, washed with ether, and a 6N hydrochloric acid aqueous solution was added to the aqueous layer to adjust the pH to about 1. After extraction with ether, the organic layer was washed successively with 5% aqueous sodium hydrogen carbonate solution and water. After drying over anhydrous magnesium sulfate, filtration and solvent distillation were performed to obtain a crude product. This was subjected to silica gel column chromatography (developing solution toluene / ethyl acetate), treated with activated carbon, and then recrystallized from methanol to obtain 3.6 g of 4-n-pentylcyclohexylmethyl 2,3-dicyano-4-hydroxyphenyl ether. It was

The compound represented by the general formula (2) can be generally obtained by the synthetic route as shown below.

[0069]

Embedded image

In the above general formula (3), R ₂ is selected from H or the following i) and ii).

I) n-alkyl group having 1 to 18 carbon atoms, more preferably n-alkyl group having 4 to 14 carbon atoms

[0072]

Embedded image

(However, p is an integer of 0 to 7, and k is 1
Is an integer from 9 to 9. Further, when k is 2 or more, it may be optically active. )

Y ₁ , Y ₂ , Y ₃ , and Y ₄ are preferably selected from the combinations shown in the following iii) to xi).

Iii) Y ₁ = Y ₃ = Y ₄ = H, Y ₂ = F iv) Y ₁ = F, Y ₂ = Y ₃ = Y ₄ = H v) Y ₁ = Y ₃ = H, Y ₂ = Y ₄ = F vi) Y ₁ = Y ₃ = F, Y ₂ = Y ₄ = H vii) Y ₁ = Y ₄ = F, Y ₂ = Y ₃ = H viii) Y ₁ = Y ₂ = F, Y ₃ = Y ₄ = H ix) Y ₁ = Y ₂ = Y ₃ = Y ₄ = F x) Y ₁ = Y ₃ = H, Y ₂ = Y ₄ = CF ₃ xi) Y ₁ = Y ₃ = CF ₃ , Y ₂ = Y ₄ = H

Specific structural formulas of the compound represented by the general formula (3) are shown below.

[0077]

[Chemical formula 26]

[0078]

Embedded image

[0079]

Embedded image

[0080]

[Chemical 29]

[0081]

Embedded image

[0082]

[Chemical 31]

[0083]

Embedded image

[0084]

[Chemical 33]

[0085]

Embedded image

The compound represented by the above general formula (3) can be generally synthesized by the following route.

[0087]

Embedded image

In the compound of the general formula (4), R ₃ is preferably selected from the following i) and ii).

I) n-alkyl group having 1 to 18 carbon atoms, more preferably n-alkyl group having 4 to 14 carbon atoms

[0090]

Embedded image

(However, p is an integer of 0 to 7, and k is 1
Is an integer from 9 to 9. Further, when k is 2 or more, it may be optically active. )

[0092]

Embedded image

The specific structural formula of the compound represented by the general formula (4) is shown below.

[0094]

Embedded image

[0095]

Embedded image

[0096]

[Chemical 40]

[0097]

Embedded image

[0098]

Embedded image

[0099]

Embedded image

[0100]

Embedded image

[0101]

Embedded image

The compound of the general formula (4) can be generally synthesized by the following route.

[0103]

Embedded image

[0104]

Embedded image

Typical synthetic examples of the compound represented by the general formula (4) are shown below.

Synthesis Example 3 Synthesis of 4-hexyloxy-2,5-dicyanophenol (1) Synthesis of 2,5-dibromo-1,4-dimethoxybenzene 200 g (1.45 mol) of hydroquinone dimethyl ether in a 2 liter reaction vessel. , 1 liter of glacial acetic acid was charged, and bromine 463 g (2.90 mol) at 10 ° C or lower
300 ml of glacial acetic acid solution was added dropwise. (Dripping in 3 hours) Then, the mixture was stirred at room temperature for 20 hours. The precipitated crystals were filtered, washed with water, washed with methanol and dried to obtain 323 g of the desired product. (Yield 75.3%)

(2) Synthesis of 2,5-dicyano-1,4-dimethoxybenzene 300 g (1.01 mol) of 2,5-dibromo-1,4-dimethoxybenzene and cuprous cyanide were placed in a 3-liter reactor. 215 g (2.40 mol) and DMF 1.5 liter were prepared, and it heated and refluxed for 8 hours. After cooling, the reaction mixture was poured into a solution of iron (III) oxide hexahydrate (500 g) in 1.6N hydrochloric acid. The precipitated crystals were filtered and washed with 20% aqueous ammonia. Subsequently, it was washed with water, washed with methanol, and dried to obtain 142 g of the desired product. (Yield 74.8
%)

(3) 2,5-Dicyanohydroquinone 100 g of 2,5-dicyano-1,4-dimethoxybenzene (5.32 × 10 ^-1 mo) in a reaction vessel of 5 liters.
l), 312.5 g (1.17 g) of anhydrous aluminum tribromide
mol) and 2.5 liters of dry benzene were charged, and the mixture was heated under reflux for 7 hours. 3 kg of crushed ice after cooling the reaction mixture
And 500 ml of concentrated hydrochloric acid were poured into the mixture. After filtering the precipitated crystals, the crystals were dissolved in a 2N caustic soda aqueous solution and the insoluble matter was filtered. The filtrate was acidified with 2N hydrochloric acid, and the precipitated crystals were filtered, washed with water and dried to obtain 35.5 g of the desired product. (Yield 41.7%)

(4) Synthesis of 4-hexyloxy-2,5-dicyanophenol 2,5-dicyanohydroquinone 35.0 g (2.19 × 10 ^-1 mol) and n-hexyl bromide 23. 8 g (1.44 × 10 ⁻¹ mol),
20.0 g of potassium carbonate (1.45 × 10 ^-1 mol),
180 ml of DMF was charged and the mixture was stirred at 120 ° C. for 3 hours. After cooling, the reaction mixture was poured into 4N hydrochloric acid (500 ml) and extracted with ethyl acetate. The organic layer was washed with water and dried (magnesium sulfate), and then the solvent was distilled off. The residue was purified by a silica gel column with n-hexane / ethyl acetate = 2/1 to obtain 17.6 g of a primary purified product. This was dissolved in ethanol, treated with activated carbon, and then recrystallized with ethanol to obtain 8.2 g of a secondary purified product. (Yield 22.9%)

In addition to the above compounds, tetrabutylammonium bromide, triethylammonium bromide, tetrabenzylammonium bromide, tetrapropylammonium bromide, tri (2-hydroxyethyl) ammonium bromide and other ionic substances are used.

The ratio of the conductive dopant contained in the chiral smectic liquid crystal composition, which is characteristic of the present invention, is 0.0 in view of the effect on the characteristics.
It is 1 to 5% by weight.

In the present invention, the chiral smectic liquid crystal composition may contain a perfluoroalkyl liquid crystal compound from the viewpoint of good compatibility with the perfluoroether liquid crystal compound. Furthermore, a so-called hydrocarbon type liquid crystalline compound having no perfluorocarbon chain can be contained as another component. The chiral smectic liquid crystal composition of the present invention contains a chiral compound.

Specific examples of the perfluoroalkyl liquid crystal compounds described above include those described in JP-A-2-142753 and those having the following structures.

[0114]

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[0115]

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[0116]

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[0117]

[Chemical 51]

[0118]

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[0119]

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[0120]

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[0121]

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[0122]

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[0123]

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[0124]

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Further, specific examples of so-called hydrocarbon type liquid crystalline compounds having no perfluorocarbon chain as other constituent components include those having the following structures.

[0126]

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[0127]

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[0128]

[Chemical formula 61]

[0129]

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[0130]

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[0131]

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[0132]

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[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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[0141]

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[0142]

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Further, specific examples of the chiral compound include those having the following structures, but the present invention is not limited thereto.

[0144]

[Table 1]

[0145]

[Table 2]

[0146]

[Table 3]

[0147]

[Table 4]

[0148]

[Table 5]

[0149]

[Chemical 76]

[0150]

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[0151]

[Table 6]

[0152]

[Table 7]

[0153]

[Table 8]

[0154]

[Table 9]

[0155]

[Table 10]

[0156]

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[0157]

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[0158]

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[0159]

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[0160]

[Chemical formula 82]

[0161]

[Chemical 83] D-1: n = 6,2R, 5R D-2: n = 6,2S, 5R D-3: n = 4,2R, 5R D-4: n = 4,2S, 5R D-5: n = 3,2R, 5R D-6: n = 2,2S, 5R D-7: n = 2,2R, 5R D-8: n = 1,2S, 5R D-9: n = 1,2R, 5R

[0162]

Embedded image D-10: n = 1 D-11: n = 2 D-12: n = 3 D-13: n = 4 D-14: n = 6 D-15: n = 10

[0163]

Embedded image D-16: n = 8 D-17: n = 10

[0164]

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[0165]

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[0166]

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[0167]

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[0168]

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[0169]

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In the chiral smectic liquid crystal composition used in the present invention, other compounds such as dyes,
Additives such as pigments, antioxidants and UV absorbers can also be included.

The liquid crystal element of the present invention usually has a structure in which a liquid crystal is sandwiched between a pair of electrode substrates, and a voltage is applied to the liquid crystal by the electrodes to control the alignment state.

FIG. 1 shows an example of the liquid crystal device of the present invention.
1 is a liquid crystal layer composed of a chiral smectic liquid crystal composition, and usually has a layer thickness of 5 μm in order to exhibit bistability.
m or less is preferable. 2 is a substrate, and glass, plastic, or the like is used. 3 is a transparent electrode such as ITO.
4 is an orientation control layer, and the film thickness of at least one orientation control layer is 200 Å or less. The alignment control layer may be formed by, for example, solution coating or vapor deposition on a substrate, sputtering, sputtering, or the like, silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride. , Inorganic materials such as silicon carbide and boron nitride, polyvinyl alcohol, polyimide, polyimide amide, polyester,
Polyamide, polyester imide, polyparaxylene,
After forming a film using an organic material such as polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane, cellulose resin, melamine resin, urea resin, acrylic resin, the surface is velvet,
It can be obtained by rubbing with a fibrous material such as cloth or paper. Further, an oblique vapor deposition method in which an oxide such as SiO or a nitride is vapor-deposited from the oblique direction of the substrate can also be used. Polyimide is preferably used.
The structure of the liquid crystal device of the present invention is not limited as long as at least one of the orientation control films has a thickness of 200 Å or less, contains the above chiral smectic liquid crystal composition as an essential component, and has a predetermined function.

In addition to the above orientation control layer, an insulating layer serving as a short-circuit preventing layer for the upper and lower substrates, or another organic material layer or inorganic material layer may be formed. Reference numeral 5 is a sealing material that bonds the substrates together. In addition to this, a gap control spacer (not shown) such as silica beads is provided between the substrates.
8 is a polarizing plate and 9 is a light source. Switching is performed in response to a switching signal from a signal power source (not shown), and it functions as a light valve for a display element or the like. Further, if the three transparent electrodes are arranged in a matrix in the upper and lower cross, pattern display and pattern exposure become possible, and they are used as, for example, displays for personal computers, word processors, etc., and light valves for printers.

The liquid crystal element of the present invention constitutes a liquid crystal device having various functions. The data format and SY which are image information having scanning line address information shown in FIGS.
A liquid crystal display device is realized by using communication synchronization means using N signals. The reference numerals in the figure are as follows.

101 chiral smectic liquid crystal display device 102 graphic controller 103 display panel 104 scanning line driving device 105 information line driving device 106 decoder 107 scanning signal generating device 108 shift register 109 line memory 110 information signal generating device 111 driving control circuit 112 GCPU 113 Host CPU 114 VRAM

The image information is generated by the graphic controller 102 on the main body side and transferred to the display panel 103 according to the signal transfer means shown in FIGS. The graphic controller 102 is a CPU
(Central processing unit, abbreviated as GCPU) and VRAM
(Image information storage memory) Host CPU 1 with 114 as a core
13 manages image information and communicates with the liquid crystal display device 101. Note that a light source is disposed on the back surface of the display panel.

In the display device of the present invention, since the liquid crystal element as the display medium has the good switching characteristics as described above, it exhibits excellent driving characteristics and reliability, high definition, high speed,
A large area display image can be obtained.

The driving method of the liquid crystal element of the present invention is, for example, JP-A-59-193426 and JP-A-59-19.
The driving method disclosed in Japanese Patent No. 3427, Japanese Patent Application Laid-Open No. 60-156046, Japanese Patent Application Laid-Open No. 60-156047 or the like can be applied.

FIG. 6 is an example of a waveform diagram of the above driving method. Further, FIG. 5 is a plan view of an example of a chiral smectic liquid crystal panel in which matrix electrodes are arranged. FIG.
In the liquid crystal panel 51, the scanning lines of the scanning electrode group 52 and the data lines of the information electrode group 53 are wired so as to intersect with each other, and the chiral smectic liquid crystal is arranged between the scanning lines and the data lines at the intersections. Has been done.

In FIG. 6A, S _S is a selected scan waveform applied to the selected scan line, S _N is a non-selected scan waveform not selected, and I _S is applied to the selected data line. selection information waveform (black), I _N represents the non-selection information signal applied to the data line which is not selected (white). In the figure the _{(I S -S S) (I} N -S S) is the voltage waveforms applied to pixels on a selected scanning line, the voltage (I _S -S _S) is applied pixel black take the display state, the voltage (I _N -
The pixel to which S _S ) is applied takes a white display state.

FIG. 6B shows the drive waveforms shown in FIG. 6A, which are time-series waveforms when the display shown in FIG. 4 is performed.

In the driving example shown in FIG. 6, the minimum application time Δt of the single polarity voltage applied to the pixel on the selected scanning line.
Corresponds to the time of the write phase t _{2, and} the time of the 1-line clear t ₁ phase is set to 2Δt.

The values of the parameters V _S , V _I and Δt of the drive waveform shown in FIG. 6 are determined by the switching characteristics of the liquid crystal material used.

FIG. 7 shows a change in the transmittance T when the drive voltage (V _S + V _I ) is changed while the bias ratio described later is kept constant, that is, a VT characteristic. Where Δ
t = 50 μsec, bias ratio V _I / (V _I + V _S ) = 1
It is fixed at / 3. The positive side of FIG. 7 is shown in FIG. 6 (I
_N -S _S), the negative side waveform shown by (I _S -S _S) is applied.

Here, V ₁ and V ₃ are called the actual drive threshold voltage and the crosstalk voltage, respectively. Also, V ₂ <V ₁ <V ₃
At this time, ΔV = (V ₃ −V ₁ ) / (V ₃ + V ₁ ) is called a voltage margin, which is a parameter of the voltage width capable of matrix driving. It can be said that V ₃ is generally present in driving a chiral smectic liquid crystal display device. Specifically, FIG.
A voltage value causing switching by V _B in waveform _{(A) (I N -S S} ). Of course, it is possible to increase the value of V ₃ by increasing the bias ratio, increasing the bias ratio corresponds to a large amplitude of a data signal, an increase in flickering in image quality, contrast Is undesirably caused.

According to our study, the bias ratio is 1/3 to 1/4.
The degree was practical. By the way, if the bias ratio is fixed, the voltage margin ΔV strongly depends on the switching characteristics of the liquid crystal material and the element configuration, and it goes without saying that an element having a large ΔV is very advantageous for matrix driving.

Similarly, the above voltage is kept constant,
It is also possible to drive by changing the voltage application time Δt. The above voltage may be used as the voltage application time as it is, and at this time, the voltage application time threshold is Δt.
₁ , the voltage application time crosstalk value is Δt _2, and (Δ
t ₂ −Δt ₁ ) / (Δt ₂ + Δt ₁ ) = ΔT is called a voltage application time margin.

At such a certain temperature, it is possible to write two states of "black" and "white" to the selected pixel depending on two directions of the information signal, and the non-selected pixel has the "black" or "white" state. The voltage margin or the voltage application time margin capable of maintaining the “white” state is unique because there is a difference depending on the liquid crystal material and the element configuration. Also,
Since the drive margin shifts even if the environmental temperature changes, in the case of an actual display device, it is necessary to set the optimal driving conditions for the liquid crystal material, the element configuration, and the environmental temperature.

[0189]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example 1, Comparative Example 1 ITO (film thickness 15)
NMP / nBC = 2 of polyimide precursor LP64 manufactured by Toray Industries, Inc. on a glass substrate with 0 nm)
/ 0.7% solution was spin-coated and baked to form polyimide (film thickness 5 nm), and then rubbing treatment was performed, and silica beads having an average particle size of 2.0 μm were dispersed as spacers on one substrate, and the other. A liquid crystal cell was prepared by facing the substrates of

On the other hand, the following liquid crystalline compounds A, B ₁ , B ₂ and B
_A liquid crystal composition α was prepared at the following composition ratio (parts by weight) of ₃ , C ₁ and C ₂ , and 1% of the following compound was added as a conductive dopant to the liquid crystal composition α to prepare a liquid crystal composition β. Both Ps of the liquid crystal composition α and the liquid crystal composition β were about 40 nC / cm ² at 30 ° C.

[0192]

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After injecting each of the liquid crystal composition α and the liquid crystal composition β into the above liquid crystal cell, 0.5 ° C./m from the isotropic phase temperature.
Liquid crystal element X (using liquid crystal composition α) and liquid crystal element Y (using liquid crystal composition β) were prepared by gradually cooling at a speed of in.

Using the liquid crystal element X and the liquid crystal element Y, the characteristics of the cell (alignment before and after driving, θa (apparent tilt angle), contrast, threshold value (switching) are measured by the following method.
speed) and subduction time) were evaluated.

The evaluation method of the sinking time will be described below.

FIG. 8A shows the state of luminance change of the white level when the cells are arranged so as to show the black state between the orthogonal polarizing plates and the pulse voltage in the white direction is applied by the photomal output. It is below the predetermined white level for the first few seconds. We call this phenomenon "subduction", and this phenomenon is associated with "afterimage" as a display panel.

As for the sinking time, a pulse having a pulse width 1.2 times the threshold value was applied, and the saturation time of the brightness change of the white level was read on an oscilloscope. The results are shown.

[0198]

[Table 11]

[0199]

Embedded image

[Comparative Examples 2 and 3] As alignment films 6,
A cell was prepared in exactly the same manner as in Example 1 except that 6-nylon was used and the thickness of the alignment film was 50 nm.

After injecting each of the liquid crystal composition α and the liquid crystal composition β into the above liquid crystal cell, 0.5 ° C./m from the isotropic phase temperature.
Liquid crystal element Z (using liquid crystal composition α) and liquid crystal element W (using liquid crystal composition β) were prepared by gradually cooling at a speed of in.

The same evaluation as in Example 1 was performed using the liquid crystal element Z and the liquid crystal element W. The results are shown.

[0203]

[Table 12]

From Example 1 and Comparative Examples 1 to 3, it was found that the liquid crystal element of the present invention was a liquid crystal element having no afterimage, high contrast and high-speed response.

[0205]

As described above, according to the liquid crystal element of the present invention, a structure with a small booklet or a layer inclination angle close to it is exhibited, and high speed, high contrast, large area, high definition, high brightness, It is intended to provide a liquid crystal device having high reliability, high quality, high brightness, and high contrast.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional structure of a liquid crystal element of the present invention.

FIG. 2 is a block diagram illustrating a display device including a liquid crystal element of the present invention and a graphics controller.

FIG. 3 is a diagram showing a timing chart of image information communication between a display device and a graphics controller.

FIG. 4 is a schematic diagram of a display pattern when actual driving is performed with the time-series driving waveform shown in FIG.

FIG. 5 is a plan view of a liquid crystal panel in which matrix electrodes are arranged.

FIG. 6 is a diagram showing an example of drive waveforms used to drive the liquid crystal element of the present invention.

FIG. 7 is a graph (VT characteristic diagram) showing a change in transmittance when a drive voltage is changed according to the present invention.

FIG. 8 is an explanatory diagram of a depression associated with afterimage development of a liquid crystal element.

[Explanation of symbols]

 1 Liquid Crystal Layer 2 Substrate 3 Transparent Electrode 4 Alignment Control Layer 5 Sealing Material 8 Polarizing Plate 9 Light Source 101 Chiral Smectic Liquid Crystal Display Device 102 Graphic Controller 103 Display Panel 104 Scanning Line Driving Device 105 Information Line Driving Device 106 Decoder 107 Scanning Signal Generating Device 108 Shift register 109 line memory 110 information signal generator 111 drive control circuit 112 GCPU 113 host CPU 114 VRAM

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (10)

[Claims] 1. The upper and lower substrates have at least electrodes and an orientation control layer, and the thickness of at least one orientation control layer is 200Å.
In the following liquid crystal device, the liquid crystal includes a fluorocarbon end portion and a hydrocarbon end portion, both end portions of which are bonded by a central nucleus, and a fluorine-containing liquid crystal compound group having a smectic mesophase or a latent smectic mesophase. Of 70% by weight or more, wherein the fluorine-containing liquid crystal compound contains 30% by weight or more of the compound containing at least one ether oxygen in the chain in the fluorocarbon terminal chain in the total amount of the liquid crystal composition. A liquid crystal element, which is a chiral smectic liquid crystal composition containing at least one substance that stably reduces the resistance of a liquid crystal layer. 2. The film thickness of at least one orientation control layer is 1
The liquid crystal device according to claim 1, wherein the liquid crystal device has a thickness of 00 Å or less. 3. The liquid crystal device according to claim 1, wherein the alignment control layer having a film thickness of 200 Å or less is made of polyimide. 4. The liquid crystal device according to claim 1, wherein different alignment treatments are performed on the upper and lower sides. 5. A fluorine-containing liquid crystal compound having a smectic mesophase or a latent smectic mesophase, which comprises the fluorocarbon terminal portion and the hydrocarbon terminal portion, the both terminal portions being bound by a central nucleus, and is -U.
Has a C _w F _{2w + 1} or _{-V (C x F 2x O)} z C y F fluorocarbon terminal chain where represented by _{2y + 1,} and at least one chain ether oxygen in the fluorocarbon terminal chains The fluorine-containing liquid crystal compound containing -V '(C
_{x 'F 2x' O) z} 'C y' F 2y '+ 1 having a fluorocarbon terminal chains containing a chain ether oxygen represented by [wherein x and x' are each (C _x F _2x O), and _{(C x 'F 2x' O} )
Independently, an integer of 1 to 10, y and y ′ are integers of 1 to 10, z and z ′ are integers of 1 to 10, and w is an integer of 1 to 20. U is -C
_{O-O- (CH 2) r} -, - O- (CH 2) r -, - (CH
_{2) r -, - OSO 2} -, - SO 2 -, - SO 2 (CH 2) r
_{-, - O (CH 2)} r -O (CH 2) r '-, - (CH 2) r
_{-N (C p H 2p + 1} ) -SO 2 -, - (CH 2) r -N (C p
H _{2p + 1} ) -CO- (where r and r ′ are independently 1 to 2
It is an integer from 0, and p is an integer from 0 to 4. ), V and V 'is a single _{bond, -COO-C r H 2r -} ,
_{-O-C r H 2r -,} - O- (C s H 2s O) t -C u H 2u -,
_{-OSO 2 -, - SO 2 -} , - SO 2 -C r H 2r -, - C r
_{H 2r -, - C r H} 2r -N (C p H 2p + 1) -SO 2 -, - C r
_{H 2r -N (C p H 2p} + 1) -CO- ( wherein r and u is an integer of from independently 1 to 20, s 1 is independently each (C _s H _2s O) Is an integer of 10; t is an integer of 1 to 6; p is an integer of 0 to 4)] The liquid crystal device according to claim 1. 6. A fluorine-containing liquid crystal compound comprising the fluorocarbon terminal portion and the hydrocarbon terminal portion, the both terminal portions being bound by a central nucleus, and having a smectic mesophase or a latent smectic mesophase is represented by the following general formula I: -1 or I-2, wherein the fluorine-containing liquid crystal compound having at least one ether oxygen in the chain in the fluorocarbon terminal chain is a compound represented by the following general formula I-2. The liquid crystal device according to any one of 1 to 4. [General Formula I-1] And a, b, and c each independently represent 0 or an integer of 1 to 3. However, a + b + c is at least 2. M ₁ ,
N ₁ is each independently -COO-, -COS-, -C.
OSe -, - COTe -, - (CH 2 CH 2) d - (d is an integer of from 1 4), - CH = CH -, - CH = N
_{-, - CH 2 -O -,} - CO -, - O-, a single bond, its orientation may be either. X, Y, Z are B ₁ ,
D ₁ and E ₁ are substituents, and each independently —H,
-Cl, -F, -Br, -I, -OH, -OCH 3, -
CN, representing the -NO _2. l, m and n are independently 0
Represents an integer of 4; G ₁ is _{-COO-C e H 2e -,} - O-
_{C e H 2e -, - C} e H 2e -, - OSOO -, - OOSO
-, - SOO -, - SOOC e H 2e -, - OC e H 2e -O
_{C e 'H 2e' -,} - C e H 2e -N (C p H 2p + 1) -SOO
_{-, - C e H 2e -N} (C p H 2p + 1) -CO- (e, e ' represents an integer of from independently 1 to 20, p is an integer of from 1 to 4.) Represents A ₁ is —O—C _f H _{2f
-O-C g H 2g + 1} , -C f H 2f -O-C g H 2g + 1, -C f H
_{2f -R ', - O-C} f H 2f -R', - COO-C f H 2f -
_{R ', - OCO-C f} H 2f -R' (R ' is -Cl, -
_{F, -CF 3, -NO 2,} -CN, -H, -COO-C f '
_{H 2f '+ 1, -OCO-} C f'' represents a _{+ 1, f, f' H} 2f, g
Each independently represents an integer of 1 to 20. ),
A ₁ may be linear or branched. R is -C _x F _{2x + 1, x} is an integer from 1 to 20. ) [General Formula I-2] And a, b, and c each independently represent 0 or an integer of 1 to 3. However, a + b + c is at least 2. M, N
Are independently -COO-, -COS-, -COS
e -, - COTe -, - (CH 2 CH 2) d - (d is an integer of from 1 4), - C≡C -, - CH = CH -, -
_{CH = N -, - CH 2} -O -, - CO -, - O-, a single bond, its orientation may be either. Each X,
Y and Z are independently -H, -Cl, -F, -Br, -I,-.
_{OH, -OCH 3, -CH 3,} -CF 3, -OCF 3, -C
N, representing the -NO _2. Each l, m, n is 0 independently
Represents an integer of 4; G is _{-COO-C e H 2e -,} - O-
_{C e H 2e -, - O} (C e "H 2e" O) t -C e 'H 2e' -, - C
_{e H 2e -, - OSOO -} , - SOO -, - SOOC e H 2e
_{-, - C e H 2e -N} (C p H 2p + 1) -SOO -, - C e H
_{2e -N (C p H 2p +} 1) -CO- (e, e ' represents an integer of from independently 1 to 20, p is an integer from 0 to 4 .e "is each (C _e "H _2e" O) independently represents an integer of 1 to 10, t is .A representative of the representative.) an integer from 1 to _{6 -O- (C f H 2f -O} ) u -C h H
_{2h + 1, - (C f} H 2f -O) u -C h H 2h + 1, -C f H 2f -
_{W, -O-C f H 2f} -W, -COO-C f H 2f -W, -O
_{CO-C f H 2f -W (} W is -Cl, -F, -CF _3, -N
_{O 2, -CN, -H, -COO} -C h H 2h + 1, -OCO-
_Represents C _h H _{2h + 1} , and f and h are each independently 1 to 20
Represents the integer. u is an integer of 1 to 10. ), A may be linear or branched. R is - (C _{x 'F 2x'}
O) _{z 'is} a _{+ 1, x''C y} ' F 2y each (C _x 'F
_{2x ′} O) are each independently an integer from 1 to 10, y ′ is an integer from 1 to 10 and z ′ is an integer from 1 to 10. ) 7. The liquid crystal composition according to claim 6, wherein the compounds represented by the general formulas I-1 and I-2 are compounds having a phenylpyrimidine core. 8. The liquid crystal device according to claim 1, wherein a liquid crystal composition containing 50% by weight or more of a fluorine-containing liquid crystal compound containing at least one ether oxygen in the chain at the end of the fluorocarbon is used. 9. The liquid crystal composition according to claim 1, wherein the amount of the substance that stably reduces the resistance of the liquid crystal layer is 0.01 to 5% by weight based on the entire liquid crystal composition. The liquid crystal element described. 10. A liquid crystal device using the liquid crystal element according to claim 1.