JP2770953B2 - Liquid crystal composition and liquid crystal device containing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal composition used for a liquid crystal device used for a liquid crystal display device or a liquid crystal-optical shutter, and more particularly, to a novel liquid crystal composition having improved response characteristics to an electric field. The present invention relates to a liquid crystal composition.

(Background technology)

Conventionally, liquid crystals have been applied in various fields as electro-optical elements. Most liquid crystal devices currently in practical use are described in, for example, “Applied Physic” by M. Schadt and W. Helfrich.
s Letters "Vo.18, No.4 (1971.2.15)," Voltage-Spendent Optical Activity of a Twisted "
Nematic Liquid Crystal "(twisted nemat
ic) type liquid crystal.

These are based on the dielectric alignment effect of liquid crystal, and use the effect that the average molecular axis direction is directed in a specific direction by an applied electric field due to the dielectric anisotropy of liquid crystal molecules.
The limit on the optical response speed of these devices is said to be milliseconds, which is too slow for many applications. On the other hand, in application to a large flat display, driving by the simple matrix method is the most influential in consideration of price, productivity, and the like. In the simple matrix system, an electrode configuration in which a scanning electrode group and a signal electrode group are configured in a matrix is employed. To drive the scanning electrode group, an address signal is sequentially and selectively applied to the scanning electrode group, and the signal electrode group is applied. Employs a time-division driving method in which a predetermined information signal is selectively applied in parallel in synchronization with an address signal.

However, when the above-described TN type liquid crystal is adopted as an element of such a driving method, a scanning electrode is selected and a region where a signal electrode is not selected, or a region where a scanning electrode is not selected and a signal electrode is selected (a so-called “half”). A finite electric field is also applied to the selected point “)”. If the difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large and the voltage threshold required for aligning the liquid crystal molecules perpendicularly to the electric field is set to this intermediate voltage value, the display element is Although it operates normally, when the number of scanning lines (N) is increased, the time during which an effective electric field is applied to one selected point while scanning the entire screen (one frame) (duty ratio) Decreases at a rate of 1 / N. For this reason, the voltage difference as an effective value between the selected point and the non-selected point when the repetitive scanning is performed becomes smaller as the number of scanning lines increases, and as a result, a decrease in image contrast and crosstalk occur. It is an inevitable drawback. Such a phenomenon is caused by a liquid crystal having no bistability (a stable state in which liquid crystal molecules are horizontally aligned with respect to an electrode surface, and are vertically aligned only when an electric field is effectively applied. ) Is essentially unavoidable when driving (i.e., repeatedly scanning) using the time accumulation effect. In order to improve this point, a voltage averaging method, a two-frequency driving method, a multiplex matrix method, and the like have already been proposed. However, any of these methods is insufficient, and a large screen or high density display device is required. At present, the number of scanning lines has reached a plateau due to a failure to sufficiently increase the number of scanning lines.

As an improvement over the disadvantages of the conventional liquid crystal device, the use of a bistable liquid crystal device has been proposed by Clark and Lager.
proposed by wall (JP-A-56-107216,
U.S. Patent No. 4367924). As the bistable liquid crystal, a ferroelectric liquid crystal having a chiral smectic C phase (SmC ^* ) or an H phase (SmH ^* ) is generally used. This ferroelectric liquid crystal has a bistable state consisting of a first optically stable state and a second optically stable state with respect to an electric field. In contrast, for example, the liquid crystal is oriented in a first optically stable state with respect to one electric field vector, and the liquid crystal is oriented in a second optically stable state with respect to the other electric field vector. In addition, this type of liquid crystal has a property (bistability) that takes one of the above two stable states in response to an applied electric field and maintains the state when no electric field is applied.

In addition to the characteristic having bistability as described above, the ferroelectric liquid crystal has an excellent characteristic of high-speed response. This is because the spontaneous polarization of the ferroelectric liquid crystal and the applied electric field directly act to induce the transition of the alignment state, and are three to four orders of magnitude faster than the response speed due to the dielectric anisotropy and the action of the electric field.

As described above, ferroelectric liquid crystals have potentially excellent properties, and by utilizing such properties,
For many of the problems of the conventional TN-type device described above, a substantial improvement is obtained. In particular, applications to high-speed optical shutters and high-density, large-screen displays are expected. For this reason, liquid crystal materials with ferroelectricity have been widely studied, but the ferroelectric liquid crystal materials developed to date have sufficient characteristics to be used in liquid crystal devices, including low-temperature operation characteristics and high-speed response. It is hard to say that it has.

Between the response time τ and the magnitude of the spontaneous polarization Ps and the viscosity η Relationship exists. Therefore, in order to increase the response speed, there are (a) increasing the magnitude Ps of the spontaneous polarization, (a) decreasing the viscosity η, and (c) increasing the applied voltage E. However, the applied voltage has an upper limit because it is driven by an IC or the like, and it is desirable that the applied voltage be as low as possible. Therefore, it is actually necessary to reduce the viscosity η or increase the value of the magnitude Ps of the spontaneous polarization.

Generally, in a ferroelectric chiral smectic liquid crystal compound having a large spontaneous polarization, the internal electric field of the cell caused by the spontaneous polarization tends to be large, and there is a tendency that restrictions on a device configuration that can take a bistable state are increased. Further, even if the spontaneous polarization is increased unnecessarily, the viscosity tends to increase with the spontaneous polarization, and as a result, the response speed may not be so high.

In addition, when the operating temperature range of the actual display is, for example, about 5 to 40 ° C., the response speed generally varies.
At present, it is about 20 times, exceeding the limit of adjustment by drive voltage and frequency.

As described above, in order to put a ferroelectric liquid crystal device into practical use, a ferroelectric chiral smectic liquid crystal composition having low viscosity, high-speed response, and small temperature dependence of response speed is required. Is done.

[Problems to be solved by the invention]

An object of the present invention is to provide a chiral smectic liquid crystal composition having a high response speed and reduced temperature dependence of the response speed so that a ferroelectric liquid crystal element can be put to practical use, and a liquid crystal using the liquid crystal composition. It is to provide an element.

[Means for Solving the Problem] The present invention provides a compound represented by the following general formula (I) (In the formula, R ₁ is a linear alkyl group of C ₁ ~C _14, R ₂
Is a linear or branched alkyl group of C ₁ ~C _14, X ₁
Is a single bond, It is. ) And at least one compound represented by the following general formula (II) (Wherein, R ₃ is an alkoxy group, an alkoxycarbonyl group,
C _1- which may be substituted by a fluorine atom or a chlorine atom
C _{18 is} a linear or branched alkyl group, R ₄ is C ₁ -C
₁₀ linear alkyl groups, X ₂ is a single bond, It is. A ferroelectric chiral smectic liquid crystal composition characterized by containing at least one of the following: and a liquid crystal element having the liquid crystal composition disposed between a pair of electrode substrates. .

Among the compounds represented by the aforementioned general formula (I), more preferred compounds are those wherein X ₁ is —O— or Can be mentioned.

Further, among the compounds represented by the general formula (II), more preferred examples of the compound include compounds in which R ₂ is a linear alkyl group.

Further, among the compounds represented by the aforementioned general formula (II),
Preferred examples of the compound include the following (II-a) to (II-a).
To h) compounds represented by the formulas:

Further, in the above formulas (II-a) to (II-h),
Preferred examples of X ₃ include a single bond, —O—, Is mentioned.

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

The compound represented by the general formula (I) can be obtained by the following synthetic route.

Synthetic route A typical synthesis example of the compound represented by the general formula (II) is shown below.

Synthesis Example 1 (Synthesis of Compound No. 2-17) 1.00 g of p-2-fluorooctyloxyphenol
(4.16 mM) was dissolved in 10 ml of pyridine and 5 ml of toluene,
A solution prepared by dissolving 1.30 g (6.00 mM) of trans-4-n-pentylcyclohexanecarboxylic acid chloride in 5 ml of toluene was added dropwise at 5 ° C. or lower for 20 to 40 minutes. After the dropwise addition, the mixture was stirred at room temperature overnight to obtain a white precipitate.

After completion of the reaction, the reaction product was extracted with benzene, and the benzene layer was further washed with distilled water. The benzene layer was dried over magnesium sulfate, and benzene was distilled off. The product was further purified using silica gel column chromatography, and further recrystallized from ethanol / methanol to obtain trans-4.
1.20 g of n-pentylcyclohexanecarboxylic acid-p-2-fluorooctyloxyphenyl ester (2.85 m
M). (Yield 68.6%) NMR data (ppm) 0.83 to 2.83 ppm (34H, m) 4.00 to 4.50 ppm (2H, q) 7.11 ppm (4H, s) 1R data (cm ^-1 ) 3456,2928,2852,1742 , 1508,1470,1248,1200,1166,113
2,854.

(Here, S ₃ , S ₄ , S ₅ , and S ₆ indicate phases having a higher degree of order than SmC ^* .) Examples of specific structural formulas of the compound represented by the general formula (II) are shown below. Shown in

A typical synthesis example of the compound represented by the general formula (II) is shown below.

Synthesis Example 2 (Synthesis of Compound No. 2-4) 1.0 g (2.94 mmol) of 5-dodecyl-2- (4'-hydroxyphenyl) pyrimidine was added to 4 ml of toluene and 4 ml of pyridine.
Dissolved in ml. 0.55 g of trans-4-n-propylcyclohexanecarboxylic acid chloride (manufactured by Kanto Chemical Co., Ltd.) dissolved in 4 ml of toluene was gradually added dropwise at 5 ° C. or lower in an ice water bath. After completion of the dropwise addition, the mixture was stirred at room temperature for 12 hours, and the reaction mixture was poured into 100 ml of ice water. After acidification with 6N hydrochloric acid, the mixture was extracted with benzene, which was washed with water, a 5% aqueous sodium hydrogen carbonate solution and water in that order. After drying over magnesium sulfate, the solvent was distilled off to obtain a cream-colored crude product. This was purified by column chromatography, and further recrystallized from a mixed solvent of ethanol and ethyl acetate to obtain 0.94 g of the title compound as white. (Yield 64.8%) Synthesis Example 3 (Synthesis of Compound No. 2-72) (I) 10 g (53.6 mmol) of trans-4-n-propylcyclohexanecarboxylic acid chloride was dissolved in 30 ml of ethanol, and a small amount of triethylamine was added thereto.
Stirred for hours. The reaction mixture was poured into ice water (100 ml), and a 6N hydrochloric acid aqueous solution was added to make the mixture acidic, followed by extraction with isopropyl ether. The organic layer was repeatedly washed with water until the washing liquid became neutral, and then dried over magnesium sulfate. After evaporating the solvent, the residue was purified by silica gel column chromatography to obtain 9.9 g of trans-4-n-propylcyclohexanecarboxylic acid ethyl ester.

(II) 0.73 g (19.1 mmol) of lithium aluminum hydride
Was added to 30 ml of dry ether, and the mixture was refluxed under heating for 1 hour. After cooling to about 10 ° C. in an ice water bath, 5 g (25.5 mmol) of trans-4-n-propylcyclohexanecarboxylic acid ethyl ester dissolved in 30 ml of dry ether was gradually added dropwise. After completion of the dropwise addition, the mixture was stirred at room temperature for 1 hour, and further heated under reflux for 1 hour. This was treated with ethyl acetate and a 6N aqueous hydrochloric acid solution, and then poured into 200 ml of ice water.

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

(III) 3.4 g (22.4 mmol) of trans-4-n-propylcyclohexylmethanol was dissolved in 20 ml of pyridine.
To this, 5.3 g of p-toluenesulfonic acid chloride dissolved in 20 ml of pyridine was added dropwise while cooling to 5 ° C. or lower in an ice water bath. After stirring at room temperature for 10 hours, the mixture was poured into 200 ml of ice water. After acidification with 6N aqueous hydrochloric acid, extraction with isopropyl ether was performed. The organic phase was repeatedly washed with water until the washing became neutral, and then dried over magnesium sulfate.
The solvent was distilled off to obtain trans-4-n-propylcyclohexylmethyl-p-toluenesulfonate.

(IV) 5-decyl-2-in 40 ml of dimethylformamide
6.3 g of (4'-hydroxyphenyl) pyrimidine (20.2 mm
ol). 1.5 g of 85% potassium hydroxide was added thereto and stirred at 100 ° C. for 1 hour. The transformer-4-n
6.9 g of -propylcyclohexylmethyl-p-toluenesulfonate was added, and the mixture was further stirred at 100 ° C for 4 hours. After the completion of the reaction, this was poured into 200 ml of ice water and extracted with benzene. The organic phase was washed with water and dried over magnesium sulfate. After evaporating the solvent, the residue was purified by silica gel column chromatography, and further recrystallized from a mixed solvent of ethanol / ethyl acetate to obtain Exemplified Compound No. 2-72.

IR (cm ^-1 ): 2920,2840,1608,1584 1428,1258,1164,800 (Sm2 is a smectic phase other than SmA and SmC, unidentified) The liquid crystal composition of the present invention comprises at least one compound represented by formula (I) and at least one compound represented by formula (II) Seeds and other liquid crystal compounds 1
It can be obtained by mixing at least a seed with an appropriate ratio. Further, the liquid crystal composition according to the present invention is preferably a ferroelectric liquid crystal composition, particularly a ferroelectric chiral smectic liquid crystal composition.

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

Each of the liquid crystal compound represented by the general formula (I) and the liquid crystal compound represented by the general formula (II) of the present invention, and one or more other liquid crystal compounds described above, or a ferroelectric liquid crystal composition containing the same (Hereinafter abbreviated as a ferroelectric liquid crystal material), the ratio of the liquid crystal compound represented by the general formula (I) or (II) of the present invention is 1 to 300 per 100 parts by weight of the ferroelectric liquid crystal material. More preferably 5 to 100 parts by weight
It is preferable to use parts by weight.

Further, when one or both of the liquid crystal compounds represented by the general formulas (I) and (II) of the present invention are used in two or more kinds, the compounding ratio with the ferroelectric liquid crystal material is the same as that of the ferroelectric liquid crystal material described above. 1 to 500 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of a mixture of two or more of one or both of the liquid crystal compounds represented by the general formulas (I) and (II) of the present invention. Is preferred.

FIG. 1 is a schematic cross-sectional view of one example of a liquid crystal device having a ferroelectric liquid crystal layer according to the present invention for explaining the configuration of a ferroelectric liquid crystal device.

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

The two glass substrates 2 are each coated with a transparent electrode made of a thin film such as In ₂ O ₃ , SnO ₂ or ITO (Indium-Tin Oxide). On top of that, a thin film of a polymer such as polyimide is rubbed with a gauze, an acetate flocking cloth or the like to form an insulating alignment control layer for arranging liquid crystals in the rubbing direction. Examples of the insulating material include silicon nitride, silicon carbide containing hydrogen, silicon oxide, boron nitride, boron nitride containing hydrogen, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, and fluoride. Form an inorganic insulating layer such as magnesium,
Polyvinyl alcohol, polyimide, polyamide imide, polyester imide, polyparaxylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin and An organic insulating substance such as a resist resin may be used as an orientation control layer, and the insulating orientation control layer may be formed in two layers, or may be a single layer of an inorganic substance orientation control layer or an organic substance insulating orientation control layer. Is also good.
If the insulating orientation control layer is inorganic, it can be formed by a vapor deposition method or the like. If it is organic, a solution in which an organic insulating material is dissolved, or a precursor solution thereof (solvent 0.1 to 20% by weight, preferably
(0.2 to 10% by weight), using a spinner coating method, a dip coating method, a screen printing method, a spray coating method, a roll coating method, or the like, and curing under predetermined curing conditions (for example, under heating) to form. Can be.

The thickness of the insulating orientation control layer is usually 30 to 1 μm, preferably 30 to 3000, and more preferably 50 to 1000.

The two glass substrates 2 are kept at an arbitrary interval by a spacer 5. For example, there is a method in which silica beads and alumina beads having a predetermined diameter are sandwiched between two glass substrates as spacers, and the periphery is sealed with a sealing material, for example, an epoxy-based adhesive. In addition, a polymer film or a glass fiber may be used as the spacer. A ferroelectric liquid crystal is sealed between the two glass substrates.

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

Further, the ferroelectric liquid crystal has an SmC ^* phase (chiral smectic C phase) in a wide temperature range including room temperature (particularly at a low temperature side), and when used as an element, a driving voltage margin and a driving temperature. A wide margin is desired.

In particular, in order to obtain a good uniform orientation property and obtain a monodomain state in the case of a device, the ferroelectric liquid crystal is changed from an isotropic phase to a Ch phase (cholesteric phase) -SmA phase (smectic A phase) -SmC ^*. It is desirable to have a phase transition series called a phase (chiral smectic C phase).

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

A polarizing plate 8 is attached to the outside of the glass substrate 2.

 Since FIG. 1 is a transparent type, a light source 9 is provided.

FIG. 2 schematically illustrates an example of a cell for explaining the operation of the ferroelectric liquid crystal element. 21a and 21b are respectively
A substrate (glass plate) coated with a transparent electrode made of a thin film such as In ₂ O ₃ , SnO ₂ or ITO (Indium-Tin Oxide), between which the liquid crystal molecule layer 22 was oriented so as to be perpendicular to the glass surface Liquid crystal of SmC ^* phase or SmH ^* phase is enclosed. A bold line 23 represents a liquid crystal molecule, and the liquid crystal molecule 23 has a dipole moment (P⊥) 24 in a direction perpendicular to the molecule. When a voltage higher than a certain threshold is applied between the electrodes on the substrates 21a and 21b, the helical structure of the liquid crystal molecules 23 is unwound, and the liquid crystal molecules 23 are oriented in such a manner that all dipole moments (P⊥) 24 are directed in the direction of the electric field. Can be changed. The liquid crystal molecules 23 have an elongated shape and exhibit refractive index anisotropy in the major axis direction and the minor axis direction. Therefore, for example, if crossed Nicol polarizers are placed above and below the glass surface, depending on the polarity of the applied voltage, It can be easily understood that the liquid crystal optical modulator has a changed optical characteristic.

The thickness of the liquid crystal cell preferably used in the optical modulation element of the present invention can be made sufficiently thin (for example, 10 μm or less). As shown in FIG. 3, as the liquid crystal layer becomes thinner, the helical structure of the liquid crystal molecules is released even when no electric field is applied, and the dipole moment Pa or Pb of the liquid crystal layer is upward (34a) or downward (34b). ). An electric field Ea or Eb having a different polarity or more than a certain threshold is applied to such a cell as shown in FIG.
When applied by 31a and 31b, the dipole moment becomes the electric field Ea
Alternatively, the liquid crystal molecules change their directions to upward 34a or downward 34b in accordance with the electric field vector of Eb, and accordingly, the liquid crystal molecules
In the stable state 33a or the second stable state 33b.

As described above, there are two advantages of using such ferroelectricity as the optical modulation element.

The first is that the response speed is extremely fast.
Means that the orientation of liquid crystal molecules has bistability. Second
If the electric field Ea is applied, the liquid crystal molecules are oriented to the first stable state 33a. This state is stable even when the electric field is turned off. When an electric field Eb in the opposite direction is applied, the liquid crystal molecules are brought into the second stable state 33.
The molecule is oriented to b and the direction of the molecule is changed, but it remains in this state even after the electric field is turned off. In addition, as long as the applied electric field Ea or Eb does not exceed a certain threshold value, each is maintained in the previous alignment state.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1 The following exemplified compounds were mixed in the following parts by weight to prepare a liquid crystal composition 1-A.

Exemplified compound 1-3,2- with respect to this liquid crystal composition 1-A
8 were mixed in the following parts by weight, respectively, to obtain a liquid crystal composition 1-B
I got

Next, the optical response was observed using cells prepared from these liquid crystal compositions according to the following procedure.

Two glass plates having a thickness of 1.1 mm were prepared, an ITO film was formed on each glass plate, a voltage application electrode was formed, and SiO ₂ was deposited thereon to form an insulating layer.

A polyimide resin precursor [Toray Co., Ltd. SP-
510] 1.0% dimethylacetamide solution at 3000 rpm.
It was applied for 15 seconds with a m spinner. After film formation, 300 minutes for 60 minutes
A heat condensation calcination treatment was performed at ℃. The film thickness at this time is about
It was 120Å.

The baked film is subjected to a rubbing treatment with an acetate flocking cloth, then washed with an isopropyl alcohol solution, and silica beads having an average particle size of 1.5 μm are sprayed on one of the glass plates. The glass plates are glued together using an adhesive sealant [Rixon Bond (Chitsuso Co., Ltd.)] so that they are parallel to each other.
The cells were dried by heating at 100 ° C for minutes. When the cell thickness of this cell was measured with a Beret phase plate, about 1.5
μm.

The liquid crystal composition 1-B described above was injected into this cell in an isotropic liquid state, and the cell was gradually cooled from the isotropic phase to 25 ° C. at a rate of 20 ° C./h, thereby producing a ferroelectric liquid crystal element.

Using this ferroelectric liquid crystal device, a peak-to-peak voltage V _PP = 25 V applied to detect an optical response under crossed Nicols (a change in the amount of transmitted light of 0 to 90%) and a response speed (hereinafter referred to as a response speed) Optical response speed) was measured. The results are shown below.

10 ° C 25 ° C 40 ° C Response speed 365μsec 95μsec 35μsec The contrast at this drive at 25 ° C is 13
, A clear switching operation was observed.

Comparative Example 1 Among the liquid crystal compositions 1-B used in Example 1, Exemplified Compound No. 2 was added to 1-A without mixing Exemplified Compound No. 1-3.
Liquid crystal composition 1-C in which only -8 was mixed with Exemplified Compound No. 2
A liquid crystal composition 1-D was prepared by mixing only Exemplified Compound No. 1-3 with 1-A without mixing -8.

Instead of using the liquid crystal composition 1-B, the liquid crystal composition 1-A,
Except for injecting 1-C and 1-D into the cell, a ferroelectric liquid crystal device was prepared in the same manner as in Example 1, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C. 25 ° C. 40 ° C. 1-A 620 μsec 170 μsec 52 μsec 1-C 515 μsec 140 μsec 45 μsec 1-D 440 μsec 120 μsec 40 μsec As is clear from Example 1 and Comparative Example 1, the liquid crystal composition 1-B according to the present invention is contained. The ferroelectric liquid crystal element
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 2 The liquid crystal composition 1-A used in Example 1 was mixed with the following exemplified compounds in the following parts by weight to obtain a liquid crystal composition 2-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

Response speed 10 ℃ 25 ℃ 40 ℃ 370μsec 93μsec 35μsec The contrast at this driving at 25 ℃ is 13
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 2 In the liquid crystal composition 2-B used in Example 2, Exemplified Compound No. 2 was added to 1-A without mixing Exemplified Compound No. 1-17.
The liquid crystal composition 2-C in which only −100, 2-104 was mixed and the exemplary compound No. 2-100, 2-104 were not mixed, and only the exemplary compound No. 1-17 was mixed with 1-A. A liquid crystal composition 2-D was prepared.

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

Response speed 10 ° C. 25 ° C. 40 ° C. 2-C 510 μsec 135 μsec 45 μsec 2-D 435 μsec 125 μsec 40 μsec As is clear from Example 2 and Comparative Example 2, a ferroelectric liquid crystal device containing the liquid crystal composition 2-B according to the present invention. Is better
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 3 The liquid crystal composition 1-A used in Example 1 was mixed with the following exemplified compounds in the following parts by weight to obtain a liquid crystal composition 3-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

Response speed 10 ℃ 25 ℃ 40 ℃ 355μsec 90μsec 35μsec The contrast at this driving at 25 ℃ is 13
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 3 Among the liquid crystal compositions 3-B used in Example 3, Exemplified Compound No. 2 was used for 1-A without mixing Exemplified Compound No. 1-22.
-9,2-12,2-15 only and a liquid crystal composition 3-C mixed with Exemplified Compound No. 2-9,2-12,2-15 without mixing Exemplified Compound No. Liquid crystal composition 3--2.
D was created.

Instead of using liquid crystal composition 1-B, liquid crystal composition 3-C
A ferroelectric liquid crystal device was prepared in exactly the same manner as in Example 1 except for injecting 3D and 3-D into the cell, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C. 25 ° C. 40 ° C. 3-C 520 μsec 140 μsec 45 μsec 3-D 450 μsec 130 μsec 40 μsec As is clear from Example 3 and Comparative Example 3, a ferroelectric liquid crystal device containing the liquid crystal composition 3-B according to the present invention. Is better
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 4 A liquid crystal composition 4 was prepared by mixing the following exemplified compounds in the following parts by weight.
-A was created.

Exemplified compound 1-10,2- with respect to this liquid crystal composition 4-A
1,2-4 were mixed in the following parts by weight to obtain a liquid crystal composition 4-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10 ℃ 25 ℃ 40 ℃ Response speed 1280μsec 320μsec 120μsec The contrast at this drive at 25 ℃ is 12
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 4 Among the liquid crystal compositions 4-B used in Example 4, Exemplified Compound No. 2 was added to 4-A without mixing Exemplified Compound No. 1-10.
Liquid crystal composition 4-C obtained by mixing -4,2-1 and Exemplified Compound No.
Exemplified compound No. 1 for 4-A without mixing 2-1 and 2-4
A liquid crystal composition 4-D in which only −10 was mixed was prepared.

Instead of using the liquid crystal composition 1-B, the liquid crystal composition 4-A,
Except that 4-C and 4-D were injected into the cell, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C 25 ° C 40 ° C 4-A 2000μsec 530μsec 158μsec 4-C 1800μsec 465μsec 145μsec 4-D 1620μsec 400μsec 135μsec As is clear from Example 4 and Comparative Example 4, the liquid crystal composition 4-B according to the present invention is contained. The ferroelectric liquid crystal element
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 5 The liquid crystal composition 4-A used in Example 4 was mixed with the following exemplified compounds in the following parts by weight to obtain a liquid crystal composition 5-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

Response speed 10 ℃ 25 ℃ 40 ℃ 1250μsec 315μsec 115μsec The contrast at this driving at 25 ℃ is 13
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 5 Among the liquid crystal compositions 5-B used in Example 5, only Exemplified Compound No. 2-73 was mixed with 4-A without mixing Exemplified Compound Nos. 1-3 and 1-16. Without mixing the liquid crystal composition 5-C and Exemplified Compound No. 2-73, Exemplified Compound No. 1 was used for 4-A.
A liquid crystal composition 5-D in which only −3 and 1-16 were mixed was prepared.

Instead of using liquid crystal composition 1-B, liquid crystal composition 5-C
A ferroelectric liquid crystal device was prepared in exactly the same manner as in Example 1 except for injecting the liquid crystal and 5-D into the cell, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C. 25 ° C. 40 ° C. 5-C 1830 μsec 470 μsec 145 μsec 5-D 1400 μsec 355 μsec 120 μsec As is clear from Example 5 and Comparative Example 5, a ferroelectric liquid crystal device containing the liquid crystal composition 5-B according to the present invention. Is better
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 6 A liquid crystal composition 6 was prepared by mixing the following exemplified compounds in the following parts by weight.
-A was created.

Exemplified compound 1-17,2- with respect to this liquid crystal composition 6-A
12,2-16 were mixed in the following parts by weight to obtain a liquid crystal composition 6-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

10 ℃ 25 ℃ 40 ℃ Response speed 1230μsec 330μsec 110μsec The contrast at this driving at 25 ℃ is 14
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 6 Among the liquid crystal compositions 6-B used in Example 6, Exemplified Compound No. 2 was added to 6-A without mixing Exemplified Compound No. 1-17.
The liquid crystal composition 6-C in which only -12 and 2-16 were mixed and the exemplary compound No. 2-12 and 2-16 were not mixed, and only the exemplary compound No. 1-17 was mixed with 4-A. A liquid crystal composition 6-D was prepared.

Instead of using the liquid crystal composition 1-B, the liquid crystal composition 6-A,
Except for injecting 6-C and 6-D into the cell, a ferroelectric liquid crystal device was prepared in the same manner as in Example 1, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C 25 ° C 40 ° C 6-A 1600 μsec 430 μsec 120 μsec 6-C 1520 μsec 410 μsec 120 μsec 6-D 1475 μsec 375 μsec 115 μsec As is clear from Example 6 and Comparative Example 6, the liquid crystal composition 6-B according to the present invention is contained. The ferroelectric liquid crystal element
The operating characteristics at low temperatures and the high-speed response are improved, and the temperature dependence of the response speed is reduced.

Example 7 The liquid crystal composition 6-A used in Example 6 was mixed with the following exemplified compounds in the following parts by weight to obtain a liquid crystal composition 7-B.

Except that this was used, a ferroelectric liquid crystal element was prepared in the same manner as in Example 1, the optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in the liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

Response speed 10 ℃ 25 ℃ 40 ℃ 1210μsec 325μsec 110μsec In addition, the contrast at this drive at 25 ℃ is 11
A clear switching operation was observed, and the bistability when the voltage application was stopped was also good.

Comparative Example 7 Among the liquid crystal compositions 7-B used in Example 7, Exemplified Compound No. 2 was added to 6-A without mixing Exemplified Compound No. 1-25.
Liquid crystal composition 7-C containing only -66 and Exemplified Compound No. 2
A liquid crystal composition 7-D was prepared by mixing only Exemplified Compound No. 1-25 with 6-A without mixing -66.

Instead of using liquid crystal composition 1-B, liquid crystal composition 7-C
A ferroelectric liquid crystal device was prepared in exactly the same manner as in Example 1 except for injecting 7-D into the cell, and the optical response speed was measured. The results are shown below.

Response speed 10 ° C. 25 ° C. 40 ° C. 7-C 1560 μsec 405 μsec 120 μsec 7-D 1430 μsec 365 μsec 115 μsec As is clear from Example 7 and Comparative Example 7, a ferroelectric liquid crystal element containing the liquid crystal composition 7-B according to the present invention. Is better
The operating characteristics at low temperatures and the high-speed response have been improved, and the temperature dependence of the response intensity has been reduced.

Examples 8 to 15 Instead of the exemplary compounds and liquid crystal compositions used in Examples 1, 4, and 6, the exemplary compounds and liquid crystal compositions shown in Table 1 were used in parts by weight, and 8-B to 15-B Was obtained.
A ferroelectric liquid crystal device was prepared in exactly the same manner as in Example 1, except that these were used. The optical response speed was measured in the same manner as in Example 1, and the switching state and the like were observed. The uniform alignment in each liquid crystal element was good, and a monodomain state was obtained. Table 1 shows the measurement results.

As is clear from Examples 8 to 15, the ferroelectric liquid crystal device containing the liquid crystalline compositions 8-B to 15-B according to the present invention has improved low-temperature operation characteristics, high-speed response speed, and high response speed. Temperature dependence is reduced.

Example 16 A ferroelectric liquid crystal device was produced in exactly the same manner as in Example 1 except that the liquid crystal compositions used in Example 1 and Comparative Example 1 were not formed of SiO ₂ , and an alignment control layer was formed only of a polyimide resin. Was prepared, and the optical response speed was measured in the same manner as in Example 1. The results are shown below.

10 ° C 25 ° C 40 ° C 1-B 355 μsec 90 μsec 35 μsec 1-C 510 μsec 135 μsec 40 μsec 1-D 420 μsec 120 μsec 40 μsec 1-A 600 μsec 160 μsec 50 μsec The device containing the dielectric liquid crystal composition is
As compared with the device containing another liquid crystal composition, the low-temperature operation characteristics were significantly improved and the temperature dependence of the response speed was reduced as in Example 1.

〔The invention's effect〕

The device containing the ferroelectric liquid crystal composition of the present invention can be a liquid crystal device having good switching characteristics and improved operation characteristics, and a liquid crystal device having reduced temperature dependence of response speed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a liquid crystal display device using a ferroelectric liquid crystal. FIGS. 2 and 3 schematically show an example of an element cell for explaining the operation of the ferroelectric liquid crystal device. 1. In the perspective view, in FIG. 1, 1 ... ferroelectric liquid crystal layer 2 ... glass substrate 3 ... transparent electrode 4 ... insulating alignment control layer 5 ... spacer 6 ... lead wire 7 ... power supply 8 ... Polarizing plate 9 Light source Io Incident light I Transmitted light In Fig. 2, 21a ... Substrate 21b ... Substrate 22 ... Ferroelectric liquid crystal layer 23 ... Liquid crystal molecules 24 ... Dipole moment (P ⊥) In FIG. 3, 31a: voltage applying means 31b: voltage applying means 33a: first stable state 33b: second stable state 34a: upward dipole moment 34b: downward dipole Moment Ea: upward electric field Eb: downward electric field

Continuation of the front page (72) Inventor Hiroyuki Kitayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (58) Field surveyed (Int. Cl. ⁶ , DB name) C09K 19/46

Claims (2)

(57) [Claims] 1. A compound represented by the following general formula (I) (In the formula, R ₁ is a linear alkyl group of C ₁ ~C _14, R ₂
Is a linear or branched alkyl group of C ₁ ~C _14, X ₁
Is a single bond, It is. ) And at least one compound represented by the following general formula (II) (Wherein, R ₃ is an alkoxy group, an alkoxycarbonyl group,
C _1- which may be substituted by a fluorine atom or a chlorine atom
C _{18 is} a linear or branched alkyl group, R ₄ is C ₁ -C
₁₀ linear alkyl groups, X ₂ is a single bond, It is. A ferroelectric chiral smectic liquid crystal composition comprising at least one of the following: 2. The following general formula (I) (In the formula, R ₁ is a linear alkyl group of C ₁ ~C _14, R ₂
Is a linear or branched alkyl group of C ₁ ~C _14, X ₁
Is a single bond, It is. ) And at least one compound represented by the following general formula (II) (Wherein, R ₃ is an alkoxy group, an alkoxycarbonyl group,
C _1- which may be substituted by a fluorine atom or a chlorine atom
C _{18 is} a linear or branched alkyl group, R ₄ is C ₁ -C
₁₀ linear alkyl groups, X ₂ is a single bond, It is. A liquid crystal device comprising a ferroelectric chiral smectic liquid crystal composition containing at least one of the following: being disposed between a pair of electrode substrates.