JP2000169852A - Liquid crystal composition and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal composition useful for e.g. liquid crystal display devices suppressed in sharp drive voltage rise on lower temperature side, with excellent high contrast and quick responsiveness by including specific liquid crystalline compounds in specified proportions. SOLUTION: This liquid crystal composition is obtained by including (A) 2-10 wt.% of at lest one kind of compound of formula I (R1 is a 1-10C alkyl, alkoxy, or the like; X1 is trans-1,4-cyclohexylene or 1,4-phenylene), (B) 10-50 wt.% of at least one kind of compound selected from the group consisting of those represented by formula II and formula III (R2 is a 1-10C alkyl, alkoxy, oxyalkyl, or the like; Y1 to Y4 are each H or F; R3 is the same as R2), and preferably, furthermore (C) 4-20 wt.% of at least one kind of compound of formula IV (R4 is the same as R2; X2 is the same as X1). The objective liquid crystal display device is produced preferably using the above liquid crystal composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal composition for liquid crystal display and a liquid crystal display device using the same. For more information, see Super Twisted Nematic (ST
The present invention relates to a nematic liquid crystal composition for liquid crystal display of the N) type and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, with the development of information equipment, particularly mobile communication equipment such as mobile phones, and portable terminal equipment such as PDAs, smaller and thinner devices have a display capacity and display quality equivalent to those of conventional CRTs. There is a growing demand for display elements with reduced power consumption. In order to meet such demands, nowadays Super Twisted Nematic (S
The liquid crystal display of the TN) type is mainly used. This method was introduced in 1984 by Shafer (TJ Scheff).
er) et al., the twist angle of which is 90 degrees in the twisted nematic (TN) method which has been widely used in the past is defeated by 180 °
It was an epoch-making thing to set between 270 degrees.
By setting such a twist angle, it is possible to achieve a considerably better contrast and a wider viewing angle as compared with the TN mode by utilizing the birefringence effect of the liquid crystal cell, and to increase the duty number (for example, up to 1/480 duty). ), The effect that the display quality is not lowered is obtained (TJ. Sc).
Heffer et al .: Appl. Phys. Lett. , 4
5 (1984) 1021).

[0003] The display element of a panel for a reflective or semi-transmissive mobile communication device such as a cellular phone is currently provided with such a ST.
N-mode liquid crystal materials are used. These liquid crystal materials are: 1) steep electro-optical characteristics to obtain high contrast; 2) exhibit high-speed response at room temperature; 3).
Relatively low viscosity to achieve a visible response time even at low temperatures, 4) Low dependence of dielectric constant on frequency at low temperatures to suppress sharp rise in drive voltage at low temperatures , 5) having a nematic phase over a wide temperature range, assuming outdoor use, and
6) There is also a need for characteristics such as operation at a relatively low drive voltage of 10 V or less.

Various studies have hitherto been made in order to satisfy this demand, but it is difficult for the conventional technology to simultaneously satisfy all of the above-mentioned required characteristics. For example, high contrast of 1) and low viscosity of 3) are required. The liquid crystal composition achieved at the same time is only a known degree (see Japanese Patent Application Laid-Open No. 5-125363).

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide high contrast, high speed response at room temperature, low temperature response that can be visually recognized, and rapid drive voltage at low temperature. An object of the present invention is to provide a nematic liquid crystal composition and a liquid crystal display device using the same, which can simultaneously achieve characteristics such as suppression of rise, availability in a wide temperature range, and a relatively low driving voltage.

[0006]

To achieve the above object, the present invention is configured as follows. (1) Formula (I) as the first component, based on the total weight

[0007]

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Wherein R ¹ is an alkyl group, alkoxy group or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and X ¹ is trans-
Shows 1,4-cyclohexylene or 1,4-phenylene. ) At least one compound represented by formula (2)
% By weight, as the second component, the formulas (II-a) and (II-b)

[0009]

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Wherein R ² is an alkyl, alkoxy or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and Y ¹ and Y ² are each independently a hydrogen atom or a fluorine atom. Is shown.)

[0011]

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Wherein R ³ is an alkyl group, alkoxy group or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and Y ³ and Y ⁴ are each independently a hydrogen atom or a fluorine atom. A liquid crystal composition comprising 10 to 50% by weight of at least one selected from the group consisting of compounds represented by the following formula: (2) Formula (III) as the third component

[0013]

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Wherein R ⁴ is an alkyl, alkoxy or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and X ² is trans-
Shows 1,4-cyclohexylene or 1,4-phenylene. ) At least one compound represented by formula (4):
(1) The liquid crystal composition according to (1), further comprising: (3) Formulas (IV-a), (IV-b) and (IV-c) as the fourth component

[0015]

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(In the formula, R ⁵ represents an alkyl group having 1 to 10 carbon atoms, and R ⁶ represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.)

[0017]

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Wherein R ⁷ and R ⁸ are each independently an alkyl, alkoxy or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and A is —CH = CH— Or a single bond.)

[0019]

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(Wherein, R ⁹ represents an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, respectively). At least one kind of one
(1) characterized by further containing up to 30% by weight.
Or the liquid crystal composition according to (2). (4) Formulas (Va) and (Vb) as the fifth component

[0021]

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Wherein R ¹⁰ is an alkyl, alkoxy or oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and R ¹¹ is
And 10 represents an alkyl group or an alkoxy group, respectively. )

[0023]

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(Wherein, R ¹² represents an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and n is 0 or 2). The liquid crystal composition according to any one of (1) to (3), further comprising 5 to 50% by weight of at least one kind selected from the group consisting of compounds. (5) A liquid crystal display device using the liquid crystal composition according to any one of (1) to (4).

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the liquid crystal composition of the present invention, the liquid crystal compound of the formula (I) used as the first component has a very large positive dielectric anisotropy. Since the first component has an effect of lowering the threshold voltage of the liquid crystal composition obtained when added to another liquid crystal compound or liquid crystal composition, the present invention provides a liquid crystal composition having a low threshold voltage in the present invention. Play an important role in doing so. In the compound represented by the formula (I), R ¹ is an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and X ¹ is trans-1. , 4-cyclohexylene or 1,4-phenylene, but R ¹ is preferably a linear alkenyl group having a prime number of 2 to 7, and X ¹ is 1,4-phenylene.

The compound represented by the formula (II-a) or (II-b) used as the second component has a relatively large positive dielectric anisotropy and an elastic constant ratio (K ₃₃ / K ₁₁ ). Is very large and the dependence of the dielectric constant at low temperature on the frequency is relatively small. This second component can increase the value of the elastic constant ratio (K ₃₃ / K ₁₁ ) of the liquid crystal composition obtained when it is added to another liquid crystal compound or liquid crystal composition, and can sharply increase the driving voltage at a low temperature. Since a sharp rise can be suppressed, the present invention plays an important role in providing a liquid crystal composition having steep electro-optical characteristics and no sharp rise in driving voltage at low temperatures. The formula (II-a)
Or, among the compounds represented by (II-b), in the former, R ² in the formula is an alkyl group, an alkoxy group, or an oxaalkyl group having 1 to 10 carbon atoms, or 2 to 10 carbon atoms.
Alkenyl groups, and those in which Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom, are widely included, and preferably, R ² is a straight-chain alkyl group having 1 to 7 carbon atoms or a C ² to C 5 In the case of the straight-chain alkenyl group, in the case of the straight-chain alkyl group, Y ¹ is a hydrogen atom or a fluorine atom and Y ² is a hydrogen atom, and in the case of the straight-chain alkenyl group, Y ¹ is Both Y ² are hydrogen atoms. In the latter, R ³ represents an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and Y ³ and Y ⁴ each independently represent a hydrogen atom or a fluorine atom. Preferably, R ³ is a linear alkyl group having 1 to 7 carbon atoms, and Y ³ and Y ⁴ are each independently a hydrogen atom or a fluorine atom.

The compound represented by the formula (III) used as the third component is a compound having a large positive dielectric anisotropy. The third component plays an important role in the present invention in that it can lower the threshold voltage of the liquid crystal composition obtained when added to another liquid crystal compound or liquid crystal composition. In the compound represented by the formula (III), R ^{4 in} the formula is an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms, or a group having 2 to 10 carbon atoms.
Alkenyl groups, wherein X ² is trans-1,4-cyclohexylene or 1,4-phenylene, and R ⁴ is preferably a straight-chain alkyl group or straight-chain alkyl group having 1 to 7 carbon atoms. Alkoxy group in which X ² is 1,4-phenylene.

Formula (IV-a) used as the fourth component,
The compound represented by (IV-b) or (IV-c) has a very low viscosity and a relatively large value of the elastic constant ratio (K ₃₃ / K ₁₁ ). This fourth component can reduce the viscosity of the liquid crystal composition obtained when added to another liquid crystal compound or liquid crystal composition and can increase the value of the elastic constant ratio (K ₃₃ / K ₁₁ ). In the present invention, it plays an important role in providing a liquid crystal composition particularly desired to realize high-speed response. Among the compounds represented by the formulas (IV-a), (IV-b) or (IV-c), those represented by the formula (IV-a) are those wherein R ⁵ in the formula has 1 to 10 carbon atoms. alkyl group, but R ⁶ can broadly include those represented by each an alkyl group or an alkoxy group having 1 to 10 carbon atoms, preferably a linear alkyl group R ⁶ is 1 to 7 carbon atoms, R ⁶ carbon atoms 1
To 7 are linear alkyl groups or linear alkoxy groups, respectively.

[0029] formula R ⁷ in (IV-b) those represented by the formula
And R ⁸ are each independently an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and A is a group represented by —CH = CH— or a single bond. But preferably R
⁷ and R ⁸ are each independently a linear alkyl group having 1 to 7 carbon atoms, and A is a single junction. In addition, the formula (IV−
The compounds represented by c) widely include those in which R ⁹ in the formula is an alkyl group, an alkoxy group or an oxaalkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms. R ⁹ is a linear alkyl group having 1 to 7 carbon atoms or a linear alkenyl group having 2 to 7 carbon atoms.

The formula (Va) used as the fifth component is
Or the compound represented by (Vb) has a high NI transition temperature and
It has low viscosity and elastic constant ratio (K₃₃/ K₁₁) Value is compared
It is a compound having a large d / p margin and a large d / p margin. This
The fifth component is in addition to other liquid crystal compounds or liquid crystal compositions.
Increase the NI transition temperature of the resulting liquid crystal composition,
The temperature dependence of the threshold voltage is reduced, and the elastic constant ratio (K
₃₃/ K₁₁) Can be increased, and d / p
In the present invention, since the
Weight in providing a liquid crystal composition having a high NI transition temperature
Play an important role. Represented by the formula (Va) or (Vb)
Of the compounds represented by the formula^TenHas 1 to 10 carbon atoms
Each of an alkyl group, an alkoxy group or an oxa group
Alkyl group or alkenyl group having 2 to 10 carbon atoms, R¹¹Is
An alkyl group or alkoxy having 1 to 10 carbon atoms
Although widely represented by the group represented by^TenIs carbon
A linear alkyl group of the formulas 1 to 7, R¹¹Is a straight chain having 1 to 7 carbon atoms
Chain alkyl group or -OCH _Threebelongs to. Also, the latter
Is R¹²Is an alkyl group having 1 to 10 carbon atoms,
Xy group or oxaalkyl group or carbon number 2-10
An alkenyl group of n is 0 or 2
Of course, preferably R¹²Is a linear alkyl having 1 to 7 carbon atoms
A linear alkenyl group having 2 to 7 carbon atoms, wherein n is 0 or
Or two.

The liquid crystal composition of the present invention contains a first component and a second component as essential components, and more preferably contains a third component to a fifth component. It is necessary that the mixing ratio of each component be equal to or less than the total weight of the liquid crystal composition. First, the mixing ratio of the first component is suitably 2 to 10% by weight. That is, if the mixing ratio is within this range, favorable composition characteristics can be achieved. However, if the mixing ratio is less than 2% by weight, a particularly low threshold voltage cannot be achieved among the objects of the present invention. If the content exceeds 10% by weight, the dependence of the dielectric constant of the obtained liquid crystal composition on the frequency is undesirably increased at low temperatures.

Next, the mixing ratio of the second component is suitably from 10 to 50% by weight. If the mixing ratio is within this range, favorable composition characteristics can be achieved. However, if the mixing ratio is less than 10% by weight, the elastic constant ratio (K ₃₃ / K) among the objects of the present invention is particularly high.
₁₁ ) value cannot be increased, and 50% by weight
If it exceeds, the viscosity of the obtained liquid crystal composition is undesirably increased.

The mixing ratio of the third component is suitably from 4 to 20% by weight. If the mixing ratio is within this range, suitable composition characteristics can be achieved, but if the mixing ratio is less than 4% by weight, a particularly low threshold voltage among the objects of the present invention cannot be achieved,
If it exceeds 20% by weight, the dependence of the dielectric constant of the obtained liquid crystal composition on the frequency is undesirably increased at low temperatures.

The mixing ratio of the fourth component is suitably from 1 to 30% by weight. If the mixing ratio is within this range, suitable composition characteristics can be achieved, but if the mixing ratio is less than 1% by weight, the viscosity of the object of the present invention cannot be particularly reduced, and the elastic constant ratio (K ₃₃ / K ₁₁ ) cannot be increased. On the other hand, when the content exceeds 30% by weight, the threshold voltage of the obtained liquid crystal composition is undesirably increased.

The mixing ratio of the fifth component is suitably from 5 to 50% by weight. When the mixing ratio is within this range, suitable composition characteristics can be achieved. However, when the mixing ratio is less than 5% by weight, the NI transition temperature cannot be particularly increased among the problems of the present invention, and the elastic constant ratio The value of (K ₃₃ / K ₁₁ ) cannot be increased. On the other hand, if it exceeds 50% by weight, the threshold voltage of the liquid crystal composition obtained is undesirably increased.

The liquid crystal composition of the present invention may contain only the above components. In addition to these components, other components such as a threshold voltage, a nematic phase temperature range, Δn, and viscosity are adjusted. The components can be contained in appropriate amounts within the scope of the present invention. Examples of such other components include the following compounds.

[0037]

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[0038]

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(In each formula, R ¹³ and R ¹⁴ are each independently an alkyl group having 1 to 10 carbon atoms, Y ⁵ is a hydrogen atom or a fluorine atom, and R ¹⁵ and R ¹⁶ are each independently a carbon atom having 1 carbon atom.
And 10 to 10 alkyl groups. )

[0040]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, each component (liquid crystalline compound)
Is represented by an abbreviation symbol, the correspondence between the two is as follows, and the content of each component means% by weight unless otherwise specified.

[0041]

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[0042]

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[0043]

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The physical property values are shown for the abbreviations in the left column understood below the reference in the right column below. NI: nematic-isotropic phase transition temperature (° C.) η: rotational viscosity at 20 ° C. (mPa · sec) Vth: threshold voltage at 25 ° C. (V) Δn: refractive index anisotropy at 25 ° C. γ: 25 Steepness at ₅₀ ° C. V ₅₀ / V ₁₀ (V ₅₀ : voltage at a transmittance of 50%, V ₁₀ : voltage at a transmittance of 10%) τ ₂₅ : response time (msec) at 1/64 duty drive at 25 ° C. τ _-20 : -20 ° C. for 1 / 64duty response time in driving _{(sec) ε 2kHz / ε 500Hz} : -20 ℃ dielectric constant dependence on the frequency (epsilon _{2 kHz:} 2 kHz of ε, ε _{500Hz: 500Hz} of epsilon) △ F: of _{-20 ℃ (V 50, 2kHz -V} 50,500Hz) (mV) (V 50, 2kHz: 2kHz of V _50, V _50,500Hz: V ₅₀ of 500 H z)

Example 1 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 7% 3-HB (F) -C 17% 2O1-BEB (F) -C 3% 3O1-BEB (F) -C 9% 3-HH-VF2 9% 1 -BHH-VF2 8% 1-BHH-2VF2 5% 3-HB (F) TB-2 8% 3-HB (F) TB-3 7% 3-HB (F) TB-4 7% 2-H2BTB- 24% 2-H2BTB-3 4% 2-H2BTB-4 3% 3-H2BTB-2 5% 3-H2BTB-3 4%

This liquid crystal composition exhibited the following physical properties. NI: 95.9 ° C. η: 27.8 mPa · sec Vth: 1.47 V Δn: 0.170 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.062, τ ₂₅ = 145 msec, τ _-20 =
2.6 sec was shown. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
957, △ F = a 67 mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change small driving voltage V ₅₀ is small.

Example 2 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 9% 3-HB (F) -C 17% 3-HB (F) -TC 15% 3-HH-VF2 12% 1-BHH-VF2 8% 1-BHH- 2VF2 7% 3-HB (F) TB-2 8% 3-HB (F) TB-3 7% 2-H2BTB-4 4% 2-H2BTB-3 4% 3-H2BTB-2 5% 3-H2BTB- 34%

The liquid crystal composition had the following physical properties. NI: 98.4 ° C. η: 19.1 mPa · sec Vth: 1.55 V Δn: 0.170 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.057, τ ₂₅ = 110 msec, τ _-20 =
2.0 sec. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
957, △ F = a 69 mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change small driving voltage V ₅₀ is small.

Comparative Example 1 The following liquid crystal composition was prepared. 1V2-BEB (F, F) -C 11% 1V2-HB-C 11% 2O1-BEB (F) -C 3% 3O1-BEB (F) -C 9% 3-HH-VF2 14% 1-BHH- VF2 10% 1-BHH-2 VF2 5% 3-HB (F) TB-2 7% 3-HB (F) TB-3 7% 3-HB (F) TB-4 3% 2-H2BTB-2 4% 2-H2BTB-3 4% 3-H2BTB-2 5% 3-H2BTB-3 4% 3-H2BTB-4 3%

This liquid crystal composition exhibited the following physical properties. NI: 100.3 ° C. η: 24.7 mPa · sec Vth: 1.56 V Δn: 0.169 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.065, τ ₂₅ = 175 msec, τ _-20 =
3.8 sec was shown. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
900, △ F = a 110 mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change significantly the driving voltage of V ₅₀ was large.

Example 3 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 8% 3-HB (F) -C 16% 2O1-BEB (F) -C 3% 3O1-BEB (F) -C 9% 3-HB-O2 5% 3 -HH-4 5% 3-HHB-1 3% 1-BHH-VF2 11% 1-BHH-2VF2 24% 3-HB (F) TB-2 8% 3-H2BTB-2 5% 3-H2BTB-3 3%

This liquid crystal composition exhibited the following physical properties. NI: 91.0 ° C. η: 22.5 mPa · sec Vth: 1.40 V Δn: 0.136 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.058, τ ₂₅ = 280 msec, τ _-20 =
5.2 sec was shown. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
955, △ F = a 68mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change small driving voltage V ₅₀ is small.

Example 4 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 8% 3-HB (F) -C 16% 2O1-BEB (F) -C 3% 3O1-BEB (F) -C 9% 3-HB-O2 7% 3 -HH-4 5% 3-HHB-1 10% 3-HHB-3 5% 1-BHH-2VF2 20% 3-HB (F) TB-2 8% 3-H2BTB-2 5% 3-H2BTB-3 4%

This liquid crystal composition exhibited the following physical properties. NI: 92.2 ° C. η: 22.4 mPa · sec Vth: 1.45 V Δn: 0.136 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.060, τ ₂₅ = 260 msec, τ _-20 =
4.6 sec was shown. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
956, ΔF = 68 mV, the dependency of the dielectric constant on the frequency at low temperature and the change of V ₅₀ were small, and the rise of the driving voltage was small.

Comparative Example 2 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 17% 3-HB-C 18% 3-HB (F) -C 10% 3-HH-4 4% 3-HHB-1 9% 3-HHB-3 3% 1-BHH-VF2 10% 1-BHH-2VF2 17% 3-HB (F) TB-2 7% 3-H2BTB-2 5%

The liquid crystal composition exhibited the following physical properties. NI: 90.6 ° C. η: 21.4 mPa · sec Vth: 1.38 V Δn: 0.136 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.065, τ ₂₅ = 290 msec, τ _-20 =
5.2 sec was shown. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
805, △ F = a 180 mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change significantly the driving voltage of V ₅₀ was large.

Example 5 A liquid crystal composition shown below was prepared. 1V2-BEB (F, F) -C 8% 3-HB (F) -C 16% 2O1-BEB (F) -C 3% 3O1-BEB (F) -C 9% 3-HB-O2 7% 3 -HH-4 5% 3-HHB-1 6% 3-HHB-3 5% 1-BHH-2VF2 20% 3-HB (F) TB-2 8% 3-H2BTB-2 5% 3-H2BTB-3 4% 3-H2BTB-4 4%

This liquid crystal composition exhibited the following physical properties. NI: 92.4 ° C. η: 23.0 mPa · sec Vth: 1.25 V Δn: 0.142 This liquid crystal composition was incorporated into an STN display device having the following parameters. Twist angle: 240 ° Tilt angle: 4 ° d / p: 0.5 d × Δn: 0.85 The physical properties of the obtained STN display element were as follows. γ = 1.061, τ ₂₅ = 250 msec, τ _-20 =
It showed 4.4 sec. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
957, △ F = a 67 mV, dependence on the frequency of the dielectric constant at low temperature, increase in both change small driving voltage V ₅₀ is small.

Example 6 A liquid crystal composition shown below was prepared. 3-HB (F, F) -C 12% 2-BEB (F) -C 7% 3-BEB (F) -C 7% 4-BEB (F) -C 13% 5-BEB (F) -C 3% 5-HH-V 18% V-HHB-1 11% 3-HHEB (F, F) -F 9% 4-HBB-V1 3% 5-HBB-V1 2% 6-HBB-V1 2% 3 -HB (F) BH-3 3% 5-HB (F) BH-3 2% 3-HHEBH-3 3% 4-HHEBH-3 3% 5-HHEBH-3 2%

This liquid crystal composition exhibited the following physical properties. NI: 100.1 ° C. η: 43.0 mPa · sec Vth: 1.26 V Δn: 0.149 This liquid crystal composition was incorporated into an STN display device having the following parameters. Torsion angle: 240
゜ Tilt angle: 4 ゜ d / p: 0.5 d × △ n: 0.85 Physical properties of the obtained STN display element were as follows. γ = 1.057, τ ₂₅ = 370 msec, τ _-20 =
5.9 sec. Also, ε _{2 kHz} / ε _{500 Hz} = 0.
940, △ F = a 71MV, dependence on the frequency of the dielectric constant at low temperature, increase in both change small driving voltage V ₅₀ is small.

[0061]

As described above, according to the present invention, a liquid crystal composition having a steep electro-optical characteristic and a relatively low viscosity can be obtained.
A nematic liquid crystal composition that simultaneously achieves the characteristics of low-temperature response that can be visually recognized, suppression of a sharp rise in driving voltage on the low-temperature side, availability in a wide temperature range, and relatively low driving voltage, and an STN method using the same. Liquid crystal display device of the present invention.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4H027 BA01 BB04 BD02 BD03 BD04 BD06 BD08 BD20 BD24 BE05 CC04 CL04 CM01 CM02 CM04 CN01 CN05 CQ02 CS04 CT01 CT02 CT03 CU01 CU05 CW01 CW02 CW03

Claims (9)

[Claims] 1. Based on the total weight, as a first component, a compound of formula (I) (Wherein, R ¹ is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
An alkenyl group of 10 to 10, X ¹ represents trans-1,4-cyclohexylene or 1,4-phenylene. 2) to 10% by weight of at least one compound represented by the formula (II-a) and (II-b) as a second component. (Wherein, R ² is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
And alkenyl groups Y ^{1 to} Y ² each independently represent a hydrogen atom or a fluorine atom. ) (Wherein, R ³ is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
And alkenyl groups, Y ³ and Y ⁴ each independently represent a hydrogen atom or a fluorine atom. ) Is selected from the group consisting of the compounds represented by
A liquid crystal composition characterized by containing by weight. 2. A compound represented by the formula (I)¹Is the carbon number
2-7 linear alkenyl groups, X¹Is 1,4-phenylene
And the compound represented by the formula (II-a) ^TwoIs the carbon number
A linear alkyl group of 1 to 7 or a linear alkyl group of 2 to 5 carbon atoms
An alkenyl group, but in the case of the linear alkyl group,
Y¹Is a hydrogen or fluorine atom and Y^TwoIs a hydrogen atom
In the case of the linear alkenyl group, Y¹And Y^TwoTogether
What is a hydrogen atom, a compound represented by the formula (II-b)
R^ThreeIs a linear alkyl group having 1 to 7 carbon atoms, Y^ThreeAnd Y^Four
Are each independently a hydrogen atom or a fluorine atom
The liquid crystal composition according to claim 1. 3. A compound of the formula (III): (Wherein, R ⁴ is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
An alkenyl group of from 10 to 10, X ² represents trans-1,4-cyclohexylene or 1,4-phenylene. The liquid crystal composition according to claim 1, further comprising 4 to 20% by weight of at least one of the compounds represented by (3). 4. The compound represented by the formula (III) wherein R ⁴ is a linear alkyl group or linear alkoxy group having 1 to 7 carbon atoms, and X ² is 1,4-phenylene. Item 3
3. The liquid crystal composition according to item 1. 5. A compound represented by the formula (IV-a) or (IV-b) as a fourth component:
And (IV-c) (In the formula, R ⁵ represents an alkyl group having 1 to 10 carbon atoms, and R ⁶ represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms.) (Wherein, R ⁷ and R ⁸ each independently represent a carbon number of 1 to 1)
0 is an alkyl group, an alkoxy group or an oxaalkyl group or an alkenyl group having 2 to 10 carbon atoms, A is
-CH = CH- or a single bond is shown. ) (Wherein, R ⁹ is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
And represents 10 to 10 alkenyl groups. 1) at least 1 to 30% by weight selected from the group consisting of the compounds represented by
The liquid crystal composition according to any one of claims 1 to 4, further comprising: 6. A compound represented by the formula (IV-a) wherein R ⁵ is a linear alkyl group having 1 to 7 carbon atoms, and R ⁶ is a linear alkyl group or a linear alkyl group having 1 to 7 carbon atoms. And a compound represented by the formula (IV-b), wherein R ⁷ and R ⁸ are each independently a linear alkyl group having 1 to 7 carbon atoms,
Is a single bond, and the compound represented by the formula (IV-c) is R ⁹
Is a linear alkyl group having 1 to 7 carbon atoms or 2 to 7 carbon atoms
The liquid crystal composition according to claim 5, which is a linear alkenyl group represented by the formula: 7. A compound of the formulas (Va) and (V-
b) embedded image (Wherein, R ¹⁰ is an alkyl group having 1 to ¹⁰ carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
An alkenyl group of 10 to 10, and R ¹¹ each represent an alkyl group or an alkoxy group having 1 to 10 carbon atoms. ) (Wherein, R ¹² is an alkyl group having 1 to 10 carbon atoms,
Alkoxy group or oxaalkyl group or carbon number 2
And 10 to 10 alkenyl groups, and n is 0 or 2. The liquid crystal composition according to any one of claims 1 to 6, further comprising 5 to 50% by weight of at least one kind selected from the group consisting of compounds represented by the formula: 8. The compound represented by the formula (Va), wherein R ¹⁰ is a linear alkyl group having 1 to 7 carbon atoms, R ¹¹ is a linear alkyl group having 1 to 7 carbon atoms or —OCH ₃ And a compound represented by the formula (Vb) wherein R ¹² is a linear alkyl group having 1 to 7 carbon atoms or a linear alkenyl group having 2 to 7 carbon atoms, and n is 0 or 2. The liquid crystal composition according to claim 7. 9. A liquid crystal display device comprising the liquid crystal composition according to claim 1.