JPH04247076A - Liquid crystal compound, liquid crystal composition containing the same, its use and liquid crystal element and display produced by using the same - Google Patents

Abstract

PURPOSE:To provide a new liquid crystal compound having improved response characteristic to electric field and useful as liquid crystal display element, etc. CONSTITUTION:The compound of formula I [R1 is 1-16C alkyl; R2 is 1-16C alkyl, halogen, trifluoromethyl, etc.; X1 is single bond, etc.; X2 is single bond, O, etc. ; A1 is group of formula II (X3 and X4 are H, halogen, methyl, etc.); A2 is group of formula III (X5 and X6 are same as X3), etc.], e.g. 2-(4- carboxyphenyl)-5-heptylpyrimidine. The compound can be produced by using a compound of formula IV (R1 is CH3, C2H5, etc.) as a starting compound. A liquid crystal composition containing at least one kind of the above compound is placed between a pair of electrode substrates to obtain a display device, etc.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a novel liquid crystal compound,
Regarding liquid crystal compositions containing the same, and liquid crystal elements and display devices using the same, more specifically, novel liquid crystal compositions with improved response characteristics to electric fields, and liquid crystal display elements and liquid crystal-optical shutters using the same. The present invention relates to a liquid crystal element used in , and a display device using the liquid crystal element for display.

0002

2. Description of the Related Art Conventionally, liquid crystals have been applied as electro-optical elements in various fields. Most of the liquid crystal elements currently in practical use are, for example, M.Sc.
hadt) and W. Helf
“Applied Physics Letters” by Rich
ters”) Vo.18, No.4 (1971.2
．． 15) P. 127-128 “Voltage D
ependent Optical Activities
Ty of a Twisted Nematic
TN shown in “liquid Crystal”
(Twisted Nematic) type liquid crystal is used.

These methods are based on the dielectric alignment effect of liquid crystals, and utilize the effect that the dielectric anisotropy of liquid crystal molecules causes the average molecular axis direction to be oriented in a specific direction by an applied electric field. The optical response speed limit of these devices is said to be milliseconds, which is too slow for many applications.

On the other hand, for application to large flat displays, driving by a simple matrix method is most effective in consideration of cost, productivity, etc. In the simple matrix method, an electrode configuration in which a scanning electrode group and a signal electrode group are arranged in a matrix is adopted, and in order to drive the electrode group, an address signal is selectively and periodically applied to the scanning electrode group, and the signal electrode group is A time division driving method is adopted in which a predetermined information signal is selectively applied in parallel in synchronization with an address signal.

However, when the above-mentioned TN type liquid crystal is adopted as an element of such a driving method, there are areas where the scanning electrode is selected and the signal electrode is not selected, or an area where the scanning electrode is not selected and the signal electrode is selected. A finite electric field is also applied to the so-called "half-selected point".

If the difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large, and the voltage threshold required to align the liquid crystal molecules perpendicular to the electric field is set to an intermediate voltage value, then Although the display element operates normally,
When increasing the number of scanning lines (N), the time during which an effective electric field is applied to one selected point while scanning the entire screen (one frame) (duty ratio) decreases by 1/N. Resulting in.

For this reason, when repeated scanning is performed, the effective voltage difference between selected points and non-selected points becomes smaller as the number of scanning lines increases, resulting in a decrease in image contrast and Crosstalk is an unavoidable drawback.

This phenomenon is caused by liquid crystals that do not have bistability (the stable state is when the liquid crystal molecules are oriented horizontally with respect to the electrode surface, and the liquid crystal molecules are oriented vertically only while an electric field is effectively applied). This is essentially an unavoidable problem that arises when driving (i.e., repeatedly scanning) an image (orientated to

In order to improve this point, a voltage averaging method,
Dual-frequency drive methods and multiplex matrix methods have already been proposed, but none of these methods are sufficient, and the ability to increase the screen size and density of display devices has reached a plateau because the number of scanning lines cannot be increased sufficiently. The current situation is that

In order to improve the drawbacks of conventional liquid crystal devices, the use of a bistable liquid crystal device has been proposed by Clark and Lagerwa.
ll) (Japanese Patent Application Laid-open No. 56-10721
6, U.S. Pat. No. 4,367,924, etc.).

As the bistable liquid crystal, a ferroelectric liquid crystal having a chiral smectic C phase (SmC* phase) or H phase (SmH* phase) is generally used.

[0012] 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. Unlike the elements, 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. Further, this type of liquid crystal has a property (bistability) of taking one of the above two stable states in response to an applied electric field and maintaining that state when no electric field is applied.

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

As described above, ferroelectric liquid crystals potentially have extremely excellent properties, and by utilizing these properties, many of the problems of the conventional TN type elements mentioned above can be solved. A fairly substantial improvement can be obtained. In particular, it is expected to be applied to high-speed optical shutters and high-density, large-screen displays. For this reason, extensive research has been conducted on liquid crystal materials with ferroelectric properties, but the ferroelectric liquid crystal materials developed to date have sufficient characteristics for use in liquid crystal devices, including low-temperature operation characteristics and high-speed response. It is difficult to say that it is equipped with the following.

The relationship between the response time τ, the magnitude of spontaneous polarization Ps, and the viscosity η is expressed by the following formula [II]

[0016]

The following relationship exists, where E is the applied electric field. Therefore, in order to increase the response speed, (a) increase the magnitude of spontaneous polarization Ps (b) viscosity η
(c) There is a method of increasing the applied electric field E. However, since the applied electric field is driven by an IC or the like, there is an upper limit, and it is desirable that the applied electric field be as low as possible. Therefore, it is actually necessary to reduce the viscosity η or increase the value of the spontaneous polarization Ps.

In general, in ferroelectric chiral smectic liquid crystal compounds that have a large spontaneous polarization, the internal electric field of the cell caused by the spontaneous polarization is also large, and there tends to be more restrictions on the device configuration that can take a bistable state. Moreover, even if the spontaneous polarization is increased unnecessarily, the viscosity tends to increase accordingly, and as a result, it is conceivable that the response speed will not become very fast.

Furthermore, when the actual operating temperature range for a display is, for example, about 5 to 40°C, the response speed generally changes by about 20 times, which exceeds the limits of adjustment by drive voltage and frequency. This is the current situation.

As described above, in order to put a ferroelectric liquid crystal element into practical use, it is necessary to have a high-speed response due to large spontaneous polarization and low viscosity, and exhibit a chiral smectic phase with small temperature dependence of response speed. A liquid crystal composition is required.

[0020]

[Problems to be Solved by the Invention] An object of the present invention is to make the above-mentioned ferroelectric liquid crystal device practical.
A liquid crystal compound effective in increasing the response speed and reducing the temperature dependence of the response speed, a liquid crystal composition containing the same, particularly a liquid crystal composition exhibiting a ferroelectric chiral smectic phase, and An object of the present invention is to provide a liquid crystal element and a display device using a liquid crystal composition.

[0021]

[Means for solving the problem] The present invention is based on the following general formula [I
]

[0022]

A liquid crystal compound represented by [25], at least one of the liquid crystal compounds
The present invention provides a liquid crystal composition containing a seed, a liquid crystal element in which the liquid crystal composition is disposed between a pair of electrode substrates, and a display device.

Among the liquid crystalline compounds represented by the formula [I], preferred compounds include [Ia] to [Ii].

[0024]

[Ia] to [Ii] More preferable compounds among the liquid crystalline compounds represented by the formulas [Ia] to [Ii] are as follows: [Iaa] to [Ii]
b] is raised.

[0025]

[Outside 27]

[0026]

[Outside 28]

[0027]

[29] is -O-. X3, X4, X5, and X6 are each preferably a hydrogen atom, a halogen atom, or a trifluoromethyl group, and more preferably a hydrogen atom, a fluorine atom, a chlorine atom, or a trifluoromethyl group.

Further, preferable R1 is the following (i) to (iv)
) is selected from. (i) n-alkyl group having 3 to 12 carbon atoms. (ii)

[0029]

(However, m is an integer of 0 to 6, and n is an integer of 1 to 8. It may also be optically active.) (iii)

[0030]

[31] (where r is an integer from 0 to 6, s is 0 or 1, t is 1
Indicates an integer between ~12. It may also be optically active. ) (iv)

[0031]

[Example 32] (However, y is 0 or 1, and x is an integer from 1 to 14.)

[0032] Preferred R2 are the following (i) to (v).
selected from. (i) n-alkyl group having 3 to 12 carbon atoms. (ii)

[0033]

[33] (However, m is an integer of 0 to 6, and n is an integer of 1 to 8. Also, it may be optically active.) (iii)

[0034]

[34] (where r is an integer from 0 to 6, s is 0 or 1, t is 1
Indicates an integer between ~12. It may also be optically active. ) (iv)

[0035]

(v) A fluorine atom, a chlorine atom, a trifluoromethyl group or a cyano group, more preferably a fluorine atom or a trifluoromethyl group.

Until now, liquid crystal compounds having a thiazole ring have been described by H. Zaschkeet al. , J.
prake. Chem. , 321, 643-654 (1
979) and International Application No. 88/08019. However, in the former, there is no description of the thiazole-2,5-diyl derivative represented by the general formula [I] of the present invention, and in the latter, although there are specific examples of thiazole-2,4-diyl derivatives, There are no specific examples of thiazole-2,5-diyl derivatives. The present inventors have discovered that the thiazole represented by the general formula [I]
As the 2,5-diyl derivative is shown later in the examples,
1, 3, 4 disclosed in international application 88/08019
It has been found that a ferroelectric chiral smectic liquid crystal composition having lower viscosity than -thiadiazole-2,5-diyl derivatives and having high-speed response can be provided.

Furthermore, as the dielectric constant ε'⊥ of the liquid crystal composition increases, the capacitance of the liquid crystal panel increases, the load applied to the IC that drives the panel increases, and the heat generated by the IC increases. As a result, serious problems such as IC malfunction and reduced durability occur, making it difficult to put liquid crystal panels into practical use. In order to solve these problems, a liquid crystal compound in which ε′⊥ is not too large is desired. Here, the present inventors further discovered that thiazole-2,5- represented by the general formula [I]
The diyl derivative is 1,3,4-thiadiazole-2,5-
It has been found that a ferroelectric chiral smectic liquid crystal composition having a smaller ε'⊥ than diyl derivatives can be obtained. From this, it can be expected that the load on the drive IC can be reduced.

Next, a general synthesis example of the liquid crystalline compound represented by the general formula [I] will be shown below.

[0039]

[Outside 36]

Next, a specific structural formula of the liquid crystal compound represented by the general formula [I] is shown below.

[0041]

[Outside 37]

[0042]

[Outside 38]

[0043]

[Outside 39]

[0044]

[Outside 40]

[0045]

[Outside 41]

[0046]

[Outside 42]

[0047]

[Outside 43]

[0048]

[Outside 44]

[0049]

[Outside 45]

[0050]

[Outside 46]

[0051]

[Outside 47]

[0052]

[Outside 48]

[0053]

[Outside 49]

[0054]

[Outside 50]

[0055]

[Outside 51]

[0056]

[Outside 52]

[0057]

[Outside 53]

[0058]

[Outside 54]

[0059]

[Outside 55]

[0060]

[Outside 56]

[0061]

[Outside 57]

[0062]

[Outside 58]

[0063]

[Outside 59]

[0064]

[Outside 60]

[0065]

[Outside 61]

[0066]

[Outside 62]

[0067]

[Outside 63]

[0068]

[Outside 64]

[0069]

[Outside 65]

[0070]

[Outside 66]

[0071]

[Outside 67]

[0072]

[Outside 68]

[0073]

[Outside 69]

[0074]

[Outside 70]

[0075]

[Outside 71]

[0076]

[Outside 72]

[0077]

[Outside 73]

[0078]

[Outside 74]

[0079]

[Outside 75]

[0080]

[Outside 76]

[0081]

[Outside 77]

[0082]

[Outside 78]

The liquid crystal composition of the present invention contains at least one liquid crystal compound represented by the general formula (I).

The liquid crystal composition according to the present invention is preferably a liquid crystal composition exhibiting a chiral smectic phase.

Other liquid crystalline compounds used in the present invention are shown in the following general formulas (III) to (XII).

[0086]

[Outside 79]

[0087]

[Outside 80]

[0088]

[Outside 81]

[0089] However, if R1' or R2' is one CH
In the case of a halogenated alkyl in which two groups are replaced with -CH halogen-, R1' or R2' is not bonded to the ring through a single bond.

R1' and R2' are preferably i) a linear alkyl group having 1 to 15 carbon atoms;

[0091]

[Outside 82]

[0092]

[Outside 83]

[0093]

[Outside 84]

[0094]

[Outside 85]

[0095]

[Outside 86]

[0096]

[Outside 87]

[0097]

[Outside 88]

[0098]

[Outside 89]

0099

[Outside 90]

[0100]

[Outside 91]

[0101]

[Outside 92]

[0102]

[Outside 93]

[0103]

[Outside 94]

[0104]

[Outside 95]

The proportion of the liquid crystal compound of the present invention in the liquid crystal composition is 1% to 80% by weight, preferably 1% by weight.
~60% by weight, more preferably 1% to 40% by weight
It is desirable to do so.

When two or more liquid crystal compounds of the present invention are used, the proportion of the mixture of two or more liquid crystal compounds of the present invention in the liquid crystal composition obtained by mixing is 1% by weight.
It is desirable that the content be 80% by weight, preferably 1% by weight - 60% by weight, and more preferably 1% by weight - 40% by weight.

Furthermore, the liquid crystal layer exhibiting ferroelectricity in the ferroelectric liquid crystal element according to the present invention can be obtained by heating the liquid crystal composition exhibiting a chiral smectic phase prepared as described above in vacuum to the isotropic liquid temperature. It is preferable to heat it, encapsulate it in an element cell, and gradually cool it to form a liquid crystal layer and return it to normal pressure.

FIG. 1 is a schematic cross-sectional view in the thickness direction of an example of a liquid crystal element having a chiral smectic liquid crystal layer of the present invention, for explaining the structure of a crystal element utilizing ferroelectricity.

Referring to FIG. 1, the liquid crystal display element has a liquid crystal layer 1 exhibiting a chiral smectic phase disposed between a pair of glass substrates 2 each provided with a transparent electrode 3 and an alignment control layer 4, and The thickness is set by a spacer 5, and a voltage can be applied from a power source 7 via a lead wire 6 between a pair of transparent electrodes 3. In addition, a pair of substrates 2
is sandwiched between a pair of crossed Nicol polarizing plates 8, and a light source 9 is arranged outside one of them.

That is, the two glass substrates 2 are each coated with In2O3, SnO2 or ITO (Indium Oxide).
A transparent electrode 3 made of a thin film such as m-Tin Oxide is coated thereon. On top of that, a thin film of polymer such as polyimide is rubbed with gauze or acetate flocked cloth.
An alignment control layer 4 is formed to align liquid crystals in the rubbing direction. The orientation control layer 4 may be made of, for example, silicon nitride, hydrogen-containing silicon nitride, silicon carbide, hydrogen-containing silicon carbide, silicon oxide, boron nitride, hydrogen-containing boron nitride, or cerium oxide. aluminum oxide, zirconium oxide,
An inorganic insulating layer such as titanium oxide or magnesium fluoride is formed, and then polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, It may have a two-layer structure in which an organic material such as polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin or photoresist resin is formed, or an inorganic material orientation control layer or a single organic material orientation control layer may be used. It may be a layer. If the alignment control film 4 is inorganic, it can be formed by a vapor deposition method, or if it is organic, it can be formed using a solution in which an organic substance is dissolved or its precursor solution (0.1 to 20% by weight in a solvent, preferably 0.2% by weight, preferably 0.2% by weight in a solvent). ~10% by weight) using a spinner coating method, dip coating method, screen printing method, spray coating method, roll coating method, etc., and under predetermined curing conditions (
For example, under heating), it can be cured and formed.

[0111] The thickness of the insulating orientation control layer is usually 30 Å to 1
μm, preferably 30 Å to 3000 Å, more preferably 50 Å to 1000 Å, is suitable.

[0112] These two glass substrates 2 are kept at an arbitrary distance by a spacer 5. For example, there is a method in which silica beads or alumina beads having a predetermined diameter are used as spacers and sandwiched between two glass substrates, and the periphery is sealed using a sealing material such as an epoxy adhesive. In addition, a polymer film or glass fiber may be used as a spacer. A liquid crystal 1 exhibiting a chiral smectic phase is sealed between these two glass substrates. Generally 0
．． The thickness is set to 5 to 20 μm, preferably 1 to 5 μm.

[0113] The transparent electrode 3 is connected to an external power source 7 by a lead wire.
It is connected to the. Further, a pair of polarizing plates 8 are bonded to the outside of the glass substrate 2, with the polarization axes of each polarizing plate being in, for example, a crossed Nicols state orthogonal to each other. The device shown in FIG. 1 is of a transmissive type and includes a light source 9.

FIG. 2 schematically depicts an example of a cell for explaining the operation of a liquid crystal element using ferroelectricity. 21a and 21b are substrates (glass plates) covered with transparent electrodes made of thin films such as In2O3; SnO2 or ITO (Indium-Tin Oxide), and the liquid crystal molecular layer 22 is arranged perpendicularly to the glass surface between them. Oriented SmC* phase or SmH* phase liquid crystal is sealed. A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 23 has a dipole moment (P⊥) 14 in a direction perpendicular to the molecule. Substrate 21a
When a voltage higher than a certain threshold is applied between the electrodes 21b and 21b, the helical structure of the liquid crystal molecules 23 is unraveled, and the liquid crystal molecules 23 change their alignment direction so that all the dipole moment (P⊥) 24 points in the direction of the electric field. be able to. liquid crystal molecule 23
has an elongated shape and exhibits refractive index anisotropy in its long and short axis directions. Therefore, for example, if crossed Nicol polarizers are placed above and below the glass surface, the optical properties will change depending on the polarity of voltage application. The changing liquid crystal optical modulation element is
easily understood.

The liquid crystal cell preferably used in the optical modulation element of the present invention can have a sufficiently thin thickness (for example, 10 μm or less). As the liquid crystal layer becomes thinner in this way, the helical structure of the liquid crystal molecules unravels even when no electric field is applied, as shown in FIG. 3, and the dipole moment Pa or Pb is directed upward (34a) or downward (34b). take either of the following states. When an electric field Ea or Eb of different polarity above a certain threshold value is applied to such a cell by the voltage applying means 31a and 31b as shown in FIG. 34a or downward 34b, and accordingly the liquid crystal molecules are in the first stable state 3.
3a or the second stable state 33b.

As mentioned above, there are two advantages to using such a ferroelectric liquid crystal element as an optical modulation element.

The first is that the response speed is extremely fast, and the second is that the alignment of liquid crystal molecules has bistability. To further explain the second point with reference to FIG. 3, for example, when the electric field Ea is applied, the liquid crystal molecules are aligned in the first stable state 33a, and this state remains stable even when the electric field is turned off. Moreover, when an electric field Eb in the opposite direction is applied, the liquid crystal molecules are aligned to the second stable state 33b and the orientation of the molecules is changed.
It remains in this state even if the electric field is turned off. Also, as long as the applied electric field Ea or Eb does not exceed a certain threshold,
Each is still maintained in its previous orientation.

[0118] By using the liquid crystal element of the present invention in a display panel section and providing a data format of image information having scanning line address information shown in FIGS. 4 and 5 and communication synchronization means using a SYNC signal, a liquid crystal display device can be obtained. Realize.

[0119] In the figure, the symbols are as follows. 101 Ferroelectric liquid crystal display device 102 Graphics controller 103 Display panel 104 Scanning line drive circuit 105 Information line drive circuit 106 Decoder 107 Scanning signal generation circuit 108 Shift register 109 Line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

Image information is generated by the graphics controller 102 on the main unit side, and is transferred to the display panel 103 according to the signal transfer means shown in FIGS. 4 and 5. The graphics controller 102 is a CP
U (Central Processing Unit, hereinafter abbreviated as GCPU 112) and VRAM (image information storage memory) 114 are responsible for management and communication of image information between the host CPU 113 and the liquid crystal display device 101, and control of the present invention The method is mainly implemented on this graphics controller 102.

Note that a light source is arranged on the back side of the display panel.

[0122] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. In the following examples, all "parts" indicate "parts by weight."

[0123]

[Example] Example 1 (Exemplary Compound 1-68) J. Org
．． Chem. , 38, 3571-3575 (1973)
2-oxodecylamine hydrochloride was synthesized according to the method of .

[0124]

[Outside 96] Ethyl isocyanoacetate 5.00g (44.2mm
Pour 60 ml of tetrahydrofuran into a 200 ml three-necked flask, and add 1,8-cyazabicyclo[5,4,0]-7-undecene (DBU) while stirring while cooling with ice and salt.
6.61 ml (44.2 mmole) was added. 13.19 g (44.2 m
mole) was dissolved in 15 ml of THF and added dropwise. After the dropwise addition was completed, the mixture was stirred at room temperature for 5 hours and 30 minutes, and then left at room temperature for 4 days. The reaction mixture was poured into water and extracted with ethyl acetate, and the organic layer was dried over sodium sulfate and then evaporated to dryness. The residue was purified by silica gel column chromatography using a 100/1 mixed solvent of toluene/ethyl acetate as an eluent to obtain 5-octyloxazole-4-carboxylic acid ethyl ester. 125 ml of 6N hydrochloric acid was added to this ester and stirred for 5 hours. After the reaction was completed, the reaction product was washed twice with ethyl acetate, and the aqueous layer was dried under reduced pressure. Acetone was added to the residue, the precipitated crystals were filtered and recrystallized with a methanol-isopropyl ether mixed solvent to obtain 3.57 g of 2-oxodecylamine hydrochloride.
(yield 38.9%).

[0125]

[Outside 97]

0.95 g of P-acetoxybenzoic acid (5.
P- synthesized using 27 mmole) and thionyl chloride
Acetoxybenzoic acid chloride and 2-oxodecylamine
1.00 g (4.81 mmole) of hydrochloride and 20 ml of dioxane were placed in a 50 ml three-necked flask. 7.1 ml of pyridine was slowly added to the mixture while heating and stirring at around 80°C, and then heating and stirring at 90-92°C for 1 hour. After the reaction was completed, the reaction product was poured into 100 ml of ice water, and the precipitated crystals were filtered, washed with water, and recrystallized with ethanol to obtain 1.23 g (yield: 70.0%) of 2-oxodecyl-(4-acetoxybenzoyl)amine. Obtained.

2-oxodecyl-(4-acetoxybenzoyl)amine 1.20 g (3.60 mmole), L
awesson's reagent 1.89g (4.67mmol
e) 20 ml of tetrahydrofuran was placed in a 50 ml eggplant flask, and the mixture was stirred under reflux for 1 hour. After the reaction was completed, the reaction product was poured into 1.41 g of sodium hydroxide dissolved in 85 ml of ice water, and the precipitated crystals were filtered, washed with water, and recrystallized with methanol to give 2-(4-acetoxyphenyl)-5-octylthiazole. 0.97 g (yield 81.3%) was obtained.

[0128] Add 0.0% potassium hydroxide to 15ml of ethanol.
2-(4-acetoxyphenyl) into the dissolved 52g
-5-octylthiazole 0.95g (2.87mmo
le) and heated and stirred at around 60° C. for 20 minutes. After the reaction was completed, the solvent was distilled off under reduced pressure, 50 ml of water was added to the residue, and 0.75 ml of hydrochloric acid was added while stirring under ice cooling. The precipitated crystals were filtered, washed with water, dissolved in ethyl acetate, dried over sodium sulfate, and the solvent was distilled off under reduced pressure. 2- which was precipitated by adding hexane to the residue
Crystals of (4-hydroxyphenyl)-5-octylthiazole were filtered. Yield 0.80g (yield 96.4%)
.

2-(4hydroxyphenyl)-5-octylthiazole 0.40 g (1.38 mmole), trans-4-pentylcyclohexanecarboxylic acid 0.3
0g (1.51mmole), dichloromethane 10ml
was placed in a 30 ml eggplant flask, and N,N'- was added under stirring at room temperature.
Dicyclohexylcarbodiimide 0.29g (1.41
mmole), 4-dimethylaminopyridine 0.04g
were added one after another, and then the mixture was stirred at room temperature for 4 hours. 1 reactant
After standing overnight at room temperature, the precipitated N,N'-dicyclohexylurea was filtered off, and the filtrate was dried under reduced pressure. The residue was purified by silica gel column chromatography (eluent: toluene/ethyl acetate: 10
0/1) and recrystallized twice with acetone to obtain 2-[4
-(trans-4-pentylcyclohexylcarbonyloxy)phenyl]-5-octylthiazole 0.54
g (yield: 83.2%). The phase transition temperature of this compound is shown below.

[0130]

[Sm3 is a higher-order smectic phase other than SmA and SmC, and is unidentified.]

Example 2 (Exemplary Compound 1-28) Example 1
2-[4-(4-fluorobenzoyloxy)phenyl]-5-octylthiazole was synthesized in the same manner using 2-(4-hydroxyphenyl)-5-octylthiazole synthesized in .

[0132]

[Outside 99]

This compound showed the following phase transition temperature.

[0134]

[Outside 100]

Example 3 (Exemplified Compound 1-93) 2-(4-carboxyphenyl)-5- synthesized by the following route
heptylpyrimidine

[0136]

[Example 101] 1.20 g (6.68 mmol) of 2-oxooctylamine hydrochloride was synthesized in the same manner as in Example 1 by converting 2.00 g (6.70 mmole) into acid chloride with thionyl chloride.
e), 30 ml of dioxane was added, and 9.8 ml of pyridine was slowly added while stirring at around 80°C, followed by heating and stirring at around 90°C for 1 hour. After the reaction was completed, the reaction product was poured into 200 ml of ice water, and the precipitated crystals were filtered and washed with water.
Recrystallize from methanol to obtain 2-oxooctyl-[4-(
2.63 g (yield 93.0%) of 5-heptylpyrimidin-2-yl)benzoyl]amine was obtained.

2-oxooctyl-[4-(5-heptylpyrimidin-2-yl)benzoyl]amine 2.60
g (6.14 mmole), 3.10 g (7.66 mmole) of Lawesson's reagent, and 40 ml of tetrahydrofuran were placed in a 100 ml eggplant flask, and stirred under reflux for 50 minutes. After the reaction was completed, 2.28 g of sodium hydroxide was added to the reaction product. Pour into 300 ml of ice water, filter the precipitated crystals, wash with water, and dissolve in toluene. After drying the toluene solution with Glauber's salt, it was evaporated to dryness under reduced pressure, and the residue was subjected to silica gel column chromatography (eluent: toluene/ethyl acetate: 100/1).
and recrystallized twice with a toluene-methanol mixed solvent to give 2-[4-(5-heptylpyrimidin-2-yl)
2.06 g (yield 79.6%) of phenyl]-5-hexylthiazole was obtained. The phase transition temperature of this compound is shown below.

[0138]

[Outside 102]

Examples 4 to 13 The compounds shown in Table I were synthesized in the same manner as in Example 3. The phase transition temperatures of these compounds are also shown in Table I.

014
0]

[Table 1]

Example 14 (Exemplified Compounds 1-10) 2-(4'-decyloxy-4-biphenyl)-5-hexylthiazole was obtained in the same manner as in Example 3 by the route shown below.

[0142]

[Outside 103]

This compound showed the following phase transition temperature.

[0144]

[Outside 104]

Example 15 (Exemplified Compound 1-39) 2-[4-(trans-
4-pentylcyclohexyl)phenyl]-5-hexylthiazole was obtained.

[0146]

[Outside 105]

The phase transition temperature of this compound is shown below.

[0148]

[Outside 106]

Example 16 (Exemplified Compound 1-191) 2-[5-(4-decyloxyphenyl)pyrazin-2-yl]-5-hexylthiazole was synthesized by the following route.

[0150]

[Outside 107]

The phase transition temperature of this compound is shown below.

[0152]

[Outside 108]

Example 17 Liquid crystal composition A was prepared by mixing the following compounds in the following parts by weight.

[0154]

[Outside 109]

Further, to this liquid crystal composition A, exemplified compound 1-109 was mixed in the following parts by weight to prepare a liquid crystal composition B.

[0156]

[Outside 110]

This shows the following phase transition temperature.

[0158]

[Outside 111]

[0159] Prepare two 0.7 mm thick glass plates,
An ITO film was formed on each glass plate to create a voltage application electrode, and SiO2 was further deposited thereon to form an insulating layer. A silane coupling agent [KBM-602 manufactured by Shin-Etsu Chemical Co., Ltd.] 0.2% isopropyl alcohol solution was applied onto a glass plate at a rotational speed of 2000 rpm. p. 1 with m spinner
It was applied for 5 seconds to perform surface treatment. Thereafter, a heat drying treatment was performed at 120° C. for 20 minutes.

[0160] Further, a polyimide resin precursor [Toray Industries, Inc. SP-
510] 1.5% dimethylacetamide solution at a rotation speed of 2000 rpm. p. It was applied for 15 seconds using a spinner. After the film was formed, a heating condensation firing process was performed at 300° C. for 60 minutes. The thickness of the coating film at this time was about 250 Å.

[0161] This fired coating was subjected to a rubbing treatment with an acetate flocked cloth, then washed with an isopropyl alcohol solution, and alumina beads with an average particle size of 2 μm were sprinkled on one glass plate, and then subjected to each rubbing treatment. The glass plates were glued together using an adhesive sealant [Rixon Bond (Chisso Corporation)] so that their axes were parallel to each other, and dried by heating at 100° C. for 60 minutes to create a cell.

[0162] Liquid crystal composition B was injected into this cell in an isotropic liquid state and slowly cooled from the isotropic phase to 25°C at a rate of 20°C/h to produce a ferroelectric liquid crystal element. The cell thickness of this cell was measured using a Bereck phase plate and was found to be approximately 2.
It was μm.

Using this ferroelectric liquid crystal element, the magnitude of spontaneous polarization Ps and the peak-to-peak voltage Vpp=20
The response speed (hereinafter referred to as optical response speed) was measured by detecting the optical response (change in amount of transmitted light from 0 to 90%) under crossed Nicols by applying a voltage of V. The results are shown below.

[0164]

[Outside 112]

Tc: transition temperature from SmC* to SmA (
℃) T: Measurement temperature of response speed and Ps (℃)

[0166]
Furthermore, using an LCR meter (YHP-4192A manufactured by Yokogawa Hewlett-Parkard), the temperature was 30°C and 20KHz.
, the dielectric constant (ε′⊥) was measured under the conditions of ±0.5V sin wave. ε′⊥=3.15

Comparative Example 1 2-[4-(5-decylpyrimidine-
2-yl)phenyl]-5-octyl-1,3,4-thiadiazole was synthesized.

[0168]

[Outside 113]

This compound exhibited the following phase transition temperature.

[0170]

[Outside 114]

[0171] This compound was mixed with the liquid crystal composition A mixed in Example 17 in the weight parts shown below to prepare a liquid crystal composition C.

[0172]

[Outside 115]

This shows the following phase transition temperature.

[0174]

[Outside 116]

A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that liquid crystal composition C was injected into the cell.
PS, optical response speed, and dielectric constant (ε′⊥) were measured. The results are shown below.

[0176]

[Outside 117]

From Example 17 and Comparative Example 1, the thiazole-2,5-diyl derivative of the present invention does not narrow the Sm*C phase compared to the 1,3,4-thiadiazole-2,5-diyl derivative. Has low viscosity and fast response, ε′⊥
was found to yield small ferroelectric chiral smectic liquid crystal compositions.

Example 18 Liquid crystal composition D was prepared by mixing the following compounds in the following parts by weight.

[0179]

[Outside 118]

[0180]

[Outside 119]

Further, to this liquid crystal composition D, the following exemplified compounds were mixed in the weight parts shown below to prepare a liquid crystal composition E.

[0182]

[Outside 120]

[0183] A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that liquid crystal composition E was injected into the cell. The optical response speed was measured by the method. The results are shown below.

[0184]

[Outside 121]

Comparative Example 2 A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that the liquid crystal composition D mixed in Example 18 was injected into the cell, and the optical response speed was measured. The results are shown below.

[0186]

[Outside 122]

Example 19 Exemplary compounds 1-22, 1-93, used in Example 18
Liquid crystal composition F was prepared by mixing the following exemplified compounds in the weight parts shown below in place of 1-165.

[0188]

[Outside 123]

A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured in the same manner as in Example 18. The measurement results are shown below.

[0190]

[Outside 124]

Example 20 Exemplary compounds 1-27, 1-41, used in Example 19
Liquid crystal composition G was prepared by mixing the following exemplified compounds in the weight parts shown below in place of 1-145.

[0192]

[Outside 125]

A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured in the same manner as in Example 18. The measurement results are shown below.

[0194]

[Outside 126]

Example 21 Liquid crystal composition H was prepared by mixing the following compounds in the following parts by weight.

[0196]

[Outside 127]

[0197]

[Outside 128]

Further, the following exemplified compounds were mixed with this liquid crystal composition H in the weight parts shown below to prepare a liquid crystal composition I.

[0199]

[Outside 129]

[0200] Except for injecting liquid crystal composition I into the cell,
A ferroelectric liquid crystal element was prepared in the same manner as in Example 17, and the optical response speed was measured in the same manner as in Example 18, and the switching state and the like were observed.

[0201] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0202]

[Outside 130]

Further, a clear switching operation was observed during driving, and good bistability was observed when voltage application was stopped.

Comparative Example 3 A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that the liquid crystal composition H mixed in Example 21 was injected into the cell, and the optical response speed was measured. The results are shown below.

[0205]

[Outside 131]

Example 22 Exemplary compounds 1-21, 1-75, used in Example 21
Liquid crystal composition J was prepared by mixing the following exemplified compounds in the weight parts shown below instead of 1-182.

[0207]

[Outside 132]

[0208] A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured and the switching state etc. was observed in the same manner as in Example 18. .

[0209] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0210]

[Outside 133]

Example 23 Exemplary compounds 1-30, 1-107 used in Example 22
, 1-192, the following exemplary compounds were mixed in the weight parts shown below to prepare a liquid crystal composition K.

[0212]

[Outside 134]

[0213] A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured and the switching state etc. was observed in the same manner as in Example 18. .

[0214] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0215]

[Outside 135]

Example 24 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition L.

[0217]

[Outside 136]

[0218]

[Outside 137]

Further, to this liquid crystal composition L, the following exemplified compounds were mixed in the weight parts shown below to prepare a liquid crystal composition M.

[0220]

[Outside 138]

[0221] A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured and the switching state etc. was observed in the same manner as in Example 18. .

[0222] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0223]

[Outside 139]

Comparative Example 4 A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that the liquid crystal composition L mixed in Example 24 was injected into the cell, and the optical response was obtained in the same manner as in Example 18. The speed was measured. The results are shown below.

[0225]

[Outside 140]

Example 25 Exemplary compounds 1-24, 1-120 used in Example 24
, 1-195, the following exemplary compounds were mixed in the weight parts shown below to prepare a liquid crystal composition N.

[0227]

[Outside 141]

[0228] A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured and the switching state etc. was observed in the same manner as in Example 18. .

[0229] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0230]

[Outside 142]

Example 26 Exemplary compounds 1-7, 1-60, 1 used in Example 25
Liquid crystal composition O was prepared by mixing the following exemplified compounds in the weight parts shown below in place of -186.

[0232]

[Outside 143]

A ferroelectric liquid crystal element was prepared in the same manner as in Example 17 except that this liquid crystal composition was used, and the optical response speed was measured in the same manner as in Example 18.

[0234] The uniform alignment within this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0235]

[Outside 144]

As is clear from Examples 18 to 26, liquid crystal compositions E, F, G, I, J, K, M, N according to the present invention
A ferroelectric liquid crystal element containing O and O has improved operating characteristics and high-speed response at low temperatures, and also has reduced temperature dependence of response speed.

Example 27 Completely the same except that a 2% aqueous solution of polyvinyl alcohol resin [PUA-117 manufactured by Kuraray Co., Ltd.] was used in place of the 1.5% dimethylacetamide solution of the polyimide resin precursor used in Example 18. A ferroelectric liquid crystal element was prepared by the method described in (1), and the optical response speed was measured in the same manner as in Example 18. The results are shown below.

[0238]

[Outside 145]

Example 28 Completely the same as Example 17 except that the orientation control layer was made only of polyimide resin without using SiO2 used in Example 18.
A ferroelectric liquid crystal element was prepared in the same manner as in Example 18.
The optical response speed was measured in the same manner. The results are shown below.

[0240]

[Outside 146]

[0241] As is clear from Examples 27 and 28, even when the element configuration is changed, the element containing the ferroelectric liquid crystal composition according to the present invention has excellent low-temperature operating characteristics as in Example 18. This has been improved, and the temperature dependence of the response speed has been reduced.

[0242]

[Effects of the Invention] If the compound of the present invention exhibits a chiral smectic phase by itself, it becomes a material that can be effectively applied to elements utilizing ferroelectricity. Furthermore, when the liquid crystal composition containing the compound of the present invention exhibits a chiral smectic phase,
A device containing the liquid crystal composition can be operated by utilizing the ferroelectricity exhibited by the liquid crystal composition. The ferroelectric liquid crystal element that can be used in this manner can be a liquid crystal element with good switching characteristics, improved low-temperature operation characteristics, and a liquid crystal element with reduced temperature dependence of response speed.

[0243] A display device in which the liquid crystal element of the present invention is used as a display element in combination with a light source, a driving circuit, etc. is a good device.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of a liquid crystal element using a liquid crystal exhibiting a chiral smectic phase.

FIG. 2 is a perspective view schematically showing an example of an element cell to explain the operation of a liquid crystal element that utilizes the ferroelectricity of liquid crystal.

FIG. 3 is a perspective view schematically showing an example of an element cell to explain the operation of a liquid crystal element that utilizes the ferroelectricity of liquid crystal.

FIG. 4 is a block configuration diagram showing a liquid crystal display device having a liquid crystal element using ferroelectricity and a graphics controller.

FIG. 5 is a timing chart of image information communication between a liquid crystal display device and a graphics controller.

[Explanation of symbols]

1 Liquid crystal layer 2 having a chiral smectic phase Glass substrate 3 Transparent electrode 4 Insulating alignment control layer 5 Spacer 6 Lead wire 7 Power source 8 Polarizing plate 9 Light source Io Incident light I Transmitted light 21a Substrate 21b Substrate 22 Having a chiral smectic phase liquid crystal layer 23
Liquid crystal molecule 24 Dipole moment (P⊥) 31a Voltage application means 31b Voltage application 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 101 Ferroelectric liquid crystal display device 102 Graphics controller 103 Display panel 104 Scanning line drive circuit 105 Information line drive circuit 106 Decoder 107 Scanning signal generation circuit 108 Shift register 109 Line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

Claims (38)

[Claims] [Claim 1] A liquid crystalline compound represented by the following general formula [I]. [Outside 1] [Claim 2] The liquid crystalline compound represented by the formula [I] is [
The liquid crystal compound according to claim 1, which is any one of [Ib] to [Ii]. [Outside 2] [Outside 3] 3. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the formula [I] is a compound represented by the following [Ia]. [Outside 4] 4. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the formula [I] is a compound represented by any one of the following formulas [Iba] to [Iib]. [Outside 5] [Outside 6] 5. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the formula [I] is the following [Iaa]. [Outside 7] 6. The liquid crystal compound according to claim 1, wherein the liquid crystal compound represented by the formula [I] is the following [Iab]. [Outside 8] 7. In the general formula [I], R1 is the following (i) -
(iv), and R2 is one of the following (i) to (v)
The liquid crystal compound according to claim 1, which is any one of the following. (i) n-alkyl group having 3 to 12 carbon atoms. (ii) [Example 9] (However, m is an integer from 0 to 6, and n is an integer from 1 to 8. It may also be optically active.) (iii) [Example 10] (However, r is an integer from 0 to 6, s is 0 or 1, t is 1
Indicates an integer between ~12. It may also be optically active. ) (iv) (However, y is 0 or 1, and x is an integer of 1 to 14.) (v) A fluorine atom or a trifluoromethyl group. 8. The liquid crystal compound according to claim 1, wherein the compound of general formula [I] is an optically active compound. 9. The liquid crystalline compound according to claim 1, wherein the compound of general formula [I] is a non-optically active compound. 10. A liquid crystal composition comprising at least one liquid crystal compound according to claim 1. 11. The liquid crystal composition according to claim 10, which contains the liquid crystal compound represented by general formula [I] in an amount of 1 to 80% by weight based on the liquid crystal composition. 12. The liquid crystal composition according to claim 10, which contains the liquid crystal compound represented by the general formula [I] in an amount of 1 to 60% by weight based on the liquid crystal composition. 13. The liquid crystal composition according to claim 10, wherein the liquid crystal compound represented by general formula [I] is contained in an amount of 1 to 40% by weight based on the liquid crystal composition. 14. The liquid crystal composition according to claim 10, wherein the liquid crystal composition has a chiral smectic phase. 15. A liquid crystal element comprising a liquid crystal composition according to claim 10 disposed between a pair of electrode substrates. 16. The liquid crystal device according to claim 15, further comprising an alignment control layer provided on the electrode substrate. 17. The liquid crystal element according to claim 16, wherein the alignment control layer is a layer subjected to a rubbing treatment. 18. The liquid crystal element according to claim 15, wherein the pair of electrode substrates is arranged to have a thickness such that the helix of liquid crystal molecules is released. 19. A display device comprising the liquid crystal element according to claim 15. Claim 20: Claim 1, wherein display is performed by switching liquid crystal molecules using ferroelectricity exhibited by the liquid crystal composition.
9. The display device according to 9. 21. The display device according to claim 19, further comprising a light source. 22. A method of using a liquid crystal composition containing a liquid crystal compound represented by the following general formula [I] for display purposes. [Outer 12] 23. The method according to claim 22, wherein the liquid crystalline compound represented by formula [I] is any one of [Ib] to [Ii]. [Outer 13] [Outer 14] 24. The method according to claim 22, wherein the liquid crystalline compound represented by the formula [I] is the following [Ia]. [Outside 15] 25. The method according to claim 22, wherein the liquid crystalline compound represented by formula [I] is one of the following formulas [Iba] to [Iib]. [Outer 16] [Outer 17] 26. The method according to claim 22, wherein the liquid crystal compound represented by formula [I] is the following [Iaa]. [Outside 18] 27. The method according to claim 22, wherein the liquid crystalline compound represented by formula [I] is the following [Iab]. [Outside 19] 28. In the general formula [I], R1 is the following (i):
~(iv), and R2 is any of the following (i)~(v)
) The method according to claim 22. (i) n-alkyl group having 3 to 12 carbon atoms. (ii) [20] (However, m is an integer of 0 to 6, n is an integer of 1 to 8. It may also be optically active.) (iii) [21] (However, r is an integer from 0 to 6, s is 0 or 1, t is 1
Indicates an integer between ~12. It may also be optically active. ) (iv) (However, y is 0 or 1, and x is an integer of 1 to 14.) (v) A fluorine atom or a trifluoromethyl group. 29. The method of use according to claim 22, wherein the compound of general formula [I] is an optically active compound. 30. The method of use according to claim 22, wherein the compound of general formula [I] is a non-optically active compound. 31. The method according to claim 22, wherein the liquid crystal compound represented by formula [I] is contained in an amount of 1 to 80% by weight based on the liquid crystal composition. 32. The method according to claim 22, wherein the liquid crystal compound represented by formula [I] is contained in an amount of 1 to 60% by weight based on the liquid crystal composition. 33. The method according to claim 22, wherein the liquid crystal compound represented by general formula [I] is contained in an amount of 1 to 40% by weight based on the liquid crystal composition. 34. The method of use according to claim 22, wherein the liquid crystal composition has a chiral smectic phase. 35. A method of using a liquid crystal element for display, in which a liquid crystal composition containing a liquid crystal compound represented by the following general formula [I] is disposed between a pair of electrode substrates. [Outer 23] 36. The method of use according to claim 35, further comprising an alignment control layer provided on the electrode substrate. 37. The method of use according to claim 36, wherein the orientation control layer is a rubbed layer. 38. The method of use according to claim 35, wherein the pair of electrode substrates is arranged to have a thickness such that the helix of liquid crystal molecules is released.