JP2003342577A - Liquid crystal composition and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition reduced in temperature and frequency dependence of threshold voltage in an operating temperature range at the same time, and having steep electrical-optical characteristics so as to realize a highly-divided drive, and to provide a liquid crystal display device by using the composition. <P>SOLUTION: This liquid crystal composition contains two, three or more kinds of compounds expressed by general formula (I) (m and n are each 0-10), and has a phase transition temperature between a nematic phase and an isotropic liquid phase of 75 to 130°C, a phase transition temperature between the nematic phase and a smetic phase or a solid phase of -60 to -20°C, and a birefringence (Δn) of 0.07-0.30. The liquid crystal display device is given by using the composition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal composition characterized in that the temperature dependence and the frequency dependence of the threshold voltage are reduced at the same time, and that the electro-optical characteristics are steep, and a liquid crystal display using the same. Regarding the device.

[0002]

2. Description of the Related Art Among liquid crystal display elements, super twisted nematic liquid crystal display elements (hereinafter referred to as STN-LCDs) are used as display devices for a wide range of applications, and various characteristics are required as the applications develop. ing. For portable display terminals, STN-LCDs capable of displaying a large amount of information and exhibiting good display characteristics in a wide operating temperature range are required. On the other hand, a method of reducing the influence of the operating temperature by adding an electrical temperature compensating circuit to the driving circuit is used. However, since an extra circuit is added, the process is complicated and the yield is reduced. Therefore, it is required that the threshold voltage of the liquid crystal display element is not easily influenced by the operating temperature within the operating temperature range.
Furthermore, in time-division driving for displaying a large amount of information, it is required that the threshold voltage of the STN-LCD does not fluctuate due to changes in the frequency of the driving voltage depending on the number of time divisions and display contents. That is, in the operating temperature range, the STN-LCD has a small temperature dependence and frequency dependence of the threshold voltage.
Is required. If these characteristics can be achieved, it is possible to obtain a good display that does not depend on the placed environmental temperature even under a severe temperature environment such as outdoors. On the other hand, for example, JP-A-4-296387, JP-A-4-300681, JP-A-7-209624, JP-A-9-157654,
Improvement methods such as WO89 / 08102 and WO91 / 08184 have been proposed. Further, Japanese Patent Laid-Open No. 2000-96059 proposes a method of improving frequency dependence. However, it cannot be said that the degree of simultaneously improving the temperature dependence and the frequency dependence of the threshold voltage of STN-LCD by these improving methods is still sufficient, and even now, liquid crystal compounds capable of high time division driving, which have improved these, Proposals for liquid crystal compositions or STN-LCDs are required.

[0003]

The problem to be solved by the present invention is to provide a steep electro-optical device capable of high time division driving in which the temperature dependence and the frequency dependence of the threshold voltage in the operating temperature range are simultaneously reduced. A liquid crystal composition having characteristics and a liquid crystal display device using the same are provided.

[0004]

In order to solve the above-mentioned problems, the inventor of the present invention uses two or more kinds of the general formula (I) at the same time so that the temperature dependence, the frequency dependence and the electrical dependence of the threshold voltage can be improved. The present invention has been completed based on the finding that the steepness of optical characteristics is surprisingly improved.

That is, the present invention has the general formula (I) as the first component.

[Chemical 11] (In the formula, m and n each independently represent 0 to 10.) Contains two or more compounds represented by a nematic phase-isotropic liquid phase transition temperature of 75 ° C to 130 ° C. C, and the smectic phase or solid phase-nematic phase transition temperature is -60 ° C to -2
Provided is a liquid crystal composition which is 0 ° C. and has a refractive index anisotropy (Δn) of 0.07 to 0.30.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION (Compound represented by the general formula (I))
A compound represented by formula (I) (hereinafter referred to as compound (I))
Is the steepness γ of the electro-optical characteristics when n is 0 or 2.
(γ = Vth / Vsat) and response speed τ are preferable, and especially
It is preferred that n is 0. Specifically, formulas (Ia) to (I-
d)

[0007]

[Chemical 12] Compounds represented by are preferred. Compound in the liquid crystal composition
The content of (I) is preferably 5 to 50 mass%, 5 to 40
Mass% is more preferable, and 5-30 mass% is especially preferable. More specifically, the compound represented by formula (Ia) or formula (Ib) is
It is preferable to contain 5 to 20% by mass. In particular, it is preferable to contain the compound represented by the formula (Ia) in an amount of 5 to 20% by mass.

Further, the liquid crystal composition more preferably contains 2 to 4 kinds of compounds represented by the general formula (I), and particularly preferably contains 2 kinds. When 2 types are contained, n is 0
Contains two kinds of compounds represented by the general formula (I), or
It is preferable that each of the compound represented by the general formula (I) in which n is 0 and the compound represented by the general formula (I) in which n is 2 contains 1 type, and n is the general formula (I). It is particularly preferable to contain two kinds of compounds represented by More specifically, formula (Ia)
And a compound represented by the formula (Ib) are preferably contained at the same time, and it is effective in increasing the response speed τ and improving the steepness γ, that is, improving the contrast (CR).

(Liquid Crystal Phase Temperature Range of Liquid Crystal Composition) The nematic phase-isotropic liquid phase transition temperature (hereinafter, referred to as Tni) of the liquid crystal composition used in the liquid crystal display device of the present invention is a threshold voltage. Higher is preferable to further reduce the temperature dependence, but if Tni is too high, the response speed deteriorates, so it is more preferably 80 ° C to 120 ° C, and 85 ° C to 110 ° C.
C is even more preferred. In addition, solid phase or smectic phase-
A lower isotropic liquid phase transition temperature (hereinafter referred to as Tn) is preferable because the temperature dependence of the threshold voltage is improved.
-30 ° C or lower is more preferable. Refractive index anisotropy (Δn) is 0.110
~ 0.195 is preferable, 0.115 to 0.185 is more preferable, 0.1
25-0.180 is particularly preferred.

The liquid crystal composition of the present invention has the general formula (II)

[Chemical 13] (In the formula, R ¹ and R ² are each independently C ^{1 to} C 16
Represents an alkyl group, an alkenyl group having 2 to 16 carbon atoms or an alkenyloxy group having 3 to 16 carbon atoms, A represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and q is Represents 0 or 1. ) Compound represented by
Say (II). ) Is preferably contained, the compound (II)
By including, the frequency dependence of the threshold voltage can be further improved. This liquid crystal composition contains the compound (II) 1
It contains 1 or 2 or more species, preferably 1 to 8 species, and more preferably 1 to 4 species. Further, the content thereof is more preferably 10 to 50% by mass, and particularly preferably 10 to 40% by mass.

A preferred example of the general formula (II) is the general formula (II-a)

[Chemical 14] (In the formula, R ³ and R ⁴ have the same meanings as R ^1. ) A compound (hereinafter, referred to as compound (II-a)).

Another preferred example of the general formula (II) is the general formula (II-b)

[Chemical 15] (In the formula, R ⁵ and R ⁶ have the same meanings as R ^1. ) (hereinafter, referred to as compound (II-b)).

The use of the compound (II-a) or the compound (II-b) is more effective for improving the frequency dependence of the threshold voltage. In particular, the compound (II-b) is effective in expanding the liquid crystal temperature range. Incidentally, the compound (II-a) and the compound (II-b)
It is more preferred to use both of these simultaneously.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the number of carbon atoms
An alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms is more preferable, and an alkenyl group having 2 to 5 carbon atoms is particularly preferable for improving electro-optical properties.

More specifically, the alkenyl group has the formula (a)
The structure of (e) is more preferable,

[Chemical 16] (In the structural formula, the right end is connected to the ring.) Among them, (c) and (d) are particularly preferable.

Further, the liquid crystal composition of the present invention has the general formula (II
I)

[Chemical 17] (In the formula, R ⁷ and R ⁸ are each independently an alkyl group or an alkoxyl group having 1 to 16 carbon atoms, or 2 to 16 carbon atoms.
Represents an alkenyl group or an alkenyloxy group having 3 to 16 carbon atoms, A and B are each independently 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4 -Phenylene group, 2,3-difluoro-1,4-phenylene group, 3,5-
Difluoro-1,4-phenylene group, 2,6-difluoro-1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,
4-phenylene group, 2,3-dimethyl-1,4-phenylene group, 3,5
-Dimethyl-1,4-phenylene group, 2,6-dimethyl-1,4-phenylene group or trans-1,4-cyclohexylene group, r and s each independently represent 0 or 1, Z ¹ and Z ²
Are each independently a single bond, -CH ₂ -CH _2- , -CH = CH-, -COO
-Or-OCO- is represented, and X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom or a fluorine atom. ) Compound represented by
By including the compound (hereinafter referred to as compound (III)), the frequency dependence of the threshold voltage can be further improved. The content of the compound (III) in the liquid crystal composition is 5 to 50% by mass.
Is more preferable, and 5 to 30 mass% is particularly preferable.

Preferred examples of the compound (III) are represented by the general formula (III
-a) ~ (III-m) represented by a compound (hereinafter, compound (III-a) ~
Say (III-m). ).

[Chemical 18]

The use of compounds (III-a) to (III-l) can further improve the temperature dependence of the threshold voltage. The use of the compound (III-m) is effective for improving the steepness γ, that is, improving the contrast CR.

Further, the liquid crystal composition of the present invention has the general formula (IV)

[Chemical 19] (In the formula, R ⁹ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and B is a 1,4-phenylene group or trans-
It represents a 1,4-cyclohexylene group, X ⁶ represents a cyano group, a fluorine atom, a trifluoromethoxy group or a difluoromethoxy group, and X ⁵ and X ⁷ each independently represent a hydrogen atom or a fluorine atom. Compound represented by () (hereinafter, compound (IV)
Say ) Is preferable, and the temperature dependence of the threshold voltage can be further improved by containing the compound (IV). The content of the compound (IV) in the liquid crystal composition is preferably 5 to 40% by mass, more preferably 10 to 30% by mass.

A preferred example of the compound (IV) is represented by the general formula (IV-a)

[Chemical 20] (Wherein R ¹⁰ has the same meaning as R ⁹ ) (hereinafter referred to as compound (IV-a)).

Another preferred example of the compound (IV) is represented by the general formula (IV-b)

[Chemical 21] (Wherein R ¹¹ has the same meaning as R ⁹ ) (hereinafter referred to as compound (IV-b)). Note that the compound
The use of (IV-a) or the compound (IV-b) is very effective for improving the steepness γ, that is, improving the contrast CR, while further improving the temperature dependence of the threshold voltage.

Further, the liquid crystal composition of the present invention has the general formula (V)

[Chemical formula 22] (In the formula, R ¹² and R ¹³ represent an alkyl group or an alkoxyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms or an alkenyloxy group having 3 to 7 carbon atoms, and D is
1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-
Fluoro-1,4-phenylene group, 2,3-difluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene group, 2,6-difluoro-1,4-phenylene group, 2- Methyl-1,4-phenylene group, 3-methyl-1,4-phenylene group, 2,3-dimethyl-1,4-phenylene group, 3,5-dimethyl-1,4-phenylene group, 2,6- Represents a dimethyl-1,4-phenylene group or trans-1,4-cyclohexylene group, Z ³ is a single bond, -CH ₂ -CH _2- , -CH = CH-, -C
Represents OO- or -OCO-. ) It is preferable to contain a compound represented by the following (hereinafter referred to as compound (V)), and the temperature dependence of the threshold voltage can be further improved. The content of the compound (V) in the liquid crystal composition is preferably 3 to 30% by mass, but 3 to 15% by mass is particularly preferable in order to balance various characteristics such as response speed τ.

Preferred examples of compound (V) are general formulas (Va) and (Vb) (hereinafter referred to as compounds (Va) and (Vb)).

[Chemical formula 23] In addition, using the compound (Va) or the compound (Vb),
The temperature dependence of the threshold voltage can be further improved.

The liquid crystal composition of the present invention containing the compound represented by the general formula (I) contains the general formulas (II) to (V) at the same time in order to obtain more excellent effects of the present invention. Is particularly preferred.

In order to obtain the effects of the present invention, a particularly preferable liquid crystal composition (hereinafter referred to as liquid crystal composition P) is the compound (I-
a) and compound (Ib) 5 to 20 mass%, compound (II) 10 to 40
Mass%, compound (III) 5 to 30 mass%, compound (IV-b) 10 to
It contains 30% by mass and 3 to 15% by mass of the compound (V). This liquid crystal composition P further reduces the temperature dependence of the threshold voltage of STN-LCD, and further reduces the driving frequency dependence of the threshold voltage at the same time. It is also preferable for improving the response speed .tau. A liquid crystal display device using such a liquid crystal composition has excellent characteristics that the temperature dependence and frequency dependence of the threshold voltage are reduced and the current value is also suppressed. Therefore, excellent display characteristics can be maintained even under a severe temperature environment such as outdoors, and a highly reliable liquid crystal display element can be provided.

For the liquid crystal composition used in the present invention, in addition to the above general formulas (I) to (V), ordinary nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, chiral agents and the like can be used.

When the liquid crystal display device using the liquid crystal composition of the present invention is a super twisted nematic (STN) liquid crystal display device, the twist angle is preferably 180 ° to 270 °,
220 ° to 260 ° is more preferable, and 230 ° to 250 ° is particularly preferable.

In the STN-LCD of the present invention, the temperature dependence of the threshold voltage is improved as compared with the conventional STN-LCD. Therefore, the STN-LCD of the present invention has a working temperature range of -20 ° C to 50 ° C.
It has good display characteristics at ° C. Specifically, conditional expression (i)

[Equation 1] (However, Vth (-20 ° C) is the threshold voltage measured by applying a rectangular wave voltage with a frequency of 100Hz at a temperature of -20 ° C, Vth (50 ° C)
Represents a threshold voltage measured by applying a rectangular wave voltage having a frequency of 100 Hz at a temperature of 50 ° C. It is possible to manufacture an STN-LCD that satisfies the temperature dependence of the threshold voltage represented by ().

Furthermore, the STN-LCD of the present invention is a conventional STN-LCD.
Compared with, the frequency dependence of the threshold voltage is significantly improved. Specifically, conditional expression (ii)

[0030]

[Equation 2] (However, Vth (5000Hz) and Vth (100Hz) represent threshold voltage measured by applying rectangular wave voltage of frequency 5000Hz and 100Hz at a temperature of -20 ° C, respectively.) It is possible to manufacture a liquid crystal display element satisfying the frequency dependence of.

In the time-divisional drive which is the driving method of STN-LCD, the frequency of the applied voltage changes depending on the number of time-divisions and the display contents. The change in voltage is visually recognized, and the display is uneven. In addition, STN-using the liquid crystal composition of the present invention
The temperature dependence of the threshold voltage of the LCD is 3 mV or less, and the frequency dependence of the threshold voltage is 0.3 or less.
-LCD can obtain good display quality without unevenness in the operating temperature range.

Therefore, the STN-LCD of the present invention reduces the temperature dependence and the frequency dependence of the threshold voltage at the same time, and is required to have 1/32 to 1/480 duty, more preferably 1 / duty, required for mobile phones and the like. It has excellent display characteristics in time division drive of 64 to 1/240 Duty and is characterized by high reliability.

The STN-LCD of the present invention may be of any display type such as transmissive type, semi-transmissive type, reflective type and the like.

[0034]

The present invention will be described in detail below with reference to examples.
The invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “mass%”.

The characteristics measured in the examples are as follows. Tni: nematic phase-isotropic liquid phase transition temperature (° C) Tn: solid phase or smectic phase-nematic phase transition temperature (° C) η: viscosity at 20 ° C (mPa · s) Δn: refractive index at 25 ° C Anisotropy Vth: Threshold voltage (V) at 25 ° C. when an STN liquid crystal display element (STN-LCD) having a cell thickness d (μm) is constructed. Applied drive waveform is 100
Hz square wave. The cell thickness d (μm) is determined by the relational expression of Δn · d = 0.90. (Vth is the drive voltage when the transmittance is 90%.) Vsat: Saturation voltage (V) at 25 ° C when an STN-LCD having a cell thickness d (μm) is constructed. The applied drive waveform is a 100Hz rectangular wave. Cell thickness d (μ
m) is determined by the relational expression of Δn ・ d = 0.90. (Vsat is the drive voltage when the transmittance is 10%.) Γ: Steepness at 25 ° C γ = Vsat / Vth τ: Response speed at 25 ° C when injected into STN-LCD
(msec)

[0036]

[Equation 3]

[Equation 4]

[Equation 5] (However, Vth (-20 ℃), Vth (25 ℃) and Vth (50 ℃) are STN-L
The frequency of CD is 100Hz at the temperature of -20 ℃, 25 ℃ and 50 ℃.
Represents a threshold voltage measured by applying a rectangular wave voltage. )

[Equation 6] (But Vth (5000Hz) and Vth (100Hz) are STN-LCD -20 ℃
Represents the threshold voltage measured by applying rectangular wave voltages having frequencies of 500 Hz and 100 Hz, respectively, at the temperature. )

The STN-LCD was manufactured as follows.
A chiral substance "S-811" (manufactured by Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal, and an organic film of "San Ever 150" (manufactured by Nissan Kagaku) was rubbed on the opposing flat transparent electrodes. STN-L with twist angle of 240 °
It was put on a CD. The chiral substance was added so that the intrinsic spiral pitch P of the mixed liquid crystal and the cell thickness d of the display cell due to the addition of the chiral substance were d / P = 0.50.

The following abbreviations are used in the description of compounds. -Terminal n (number): -C _n H _{2n + 1} ndm-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1 --T-: -C≡C- -ndm:- (C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1 ) -F: -F -On: -OC _n H _{2n + 1} -VO-: -COO- -CN: -C≡N- Z-: -CH = NN = CH-

[Chemical formula 24]

For example, the following abbreviations are used.

[Chemical 25]

(Example 1 and Comparative Example 1) Liquid crystal composition No. 1 (Example 1) and liquid crystal composition M1 (Comparative Example 1) were prepared. Also,
STN-LCDs were produced using these liquid crystal compositions. table 1
Shows the composition ratios of these liquid crystal compositions and the characteristic measured values of STN-LCD using the liquid crystal compositions.

[0041]

[Table 1] For comparison with the liquid crystal composition No. 1 (Example 1) having the composition ratio shown in Table 1, the liquid crystal composition M1

(Comparative Example 1) [described in JP 2000-96059 A, example
1: Liquid crystal mixture A-1] was prepared. From the characteristic measured value of STN-LCD, compared with Comparative Example 1, STN-LCD using the liquid crystal composition of Example 1, the steepness γ is significantly improved, at the same time, the temperature dependence of the threshold voltage. It can be seen that the degree and frequency dependence are improved.

Example 2 A liquid crystal composition No. 2 (Example 2) was prepared. Moreover, STN-LCD using this liquid crystal composition was produced. Table 2 shows the composition ratios of the liquid crystal composition and the liquid crystal composition M1 (Comparative Example 1), and the characteristic measured values of the STN-LCD using the liquid crystal composition.

[0044]

[Table 2]

From the characteristic measured values of STN-LCD shown in Table 2, as compared with Comparative Example 1, the STN-LCD using the liquid crystal composition of Example 2 was compared.
It can be seen that the steepness γ of the LCD is significantly improved, and at the same time, the temperature dependence and frequency dependence of the threshold voltage are improved.

Example 3 A liquid crystal composition No. 3 (Example 3) was prepared. Moreover, STN-LCD using this liquid crystal composition was produced. Table 3 shows the composition ratios of the liquid crystal composition and the liquid crystal composition M1 (Comparative Example 1), and the characteristic measured values of STN-LCD using the liquid crystal composition.

[0047]

[Table 3]

From the characteristic measured values of STN-LCD shown in Table 3, as compared with Comparative Example 1, the STN-LCD using the liquid crystal composition of Example 3 was compared.
It can be seen that the LCD has improved steepness γ and, at the same time, improved temperature dependence and frequency dependence of the threshold voltage.

[0049]

EFFECTS OF THE INVENTION The present invention provides a liquid crystal composition characterized by greatly improving the steepness γ and improving the temperature dependence and frequency dependence of the threshold voltage at the same time. STN-LC with significantly improved display quality in the range
You can get D. Therefore, the STN-LCD of the present invention has good display quality with little display unevenness in the operating temperature range, and has excellent contrast.

Claims (11)

[Claims] 1. A compound of the general formula (I): (In the formula, m and n each independently represent 0 to 10.) Contains two or more compounds represented by a nematic phase-isotropic liquid phase transition temperature of 75 ° C to 130 ° C. C, and the smectic phase or solid phase-nematic phase transition temperature is -60 ° C to -2
A liquid crystal composition, which is at 0 ° C. and has a refractive index anisotropy (Δn) of 0.070 to 0.30. 2. As general formula (I), formulas (Ia) to (Id): 2. The liquid crystal composition according to claim 1, containing a compound selected from the group of compounds represented by: 3. A compound represented by the general formula (II): (In the formula, R ¹ and R ² are each independently C ^{1 to} C 16
Represents an alkyl group, an alkenyl group having 2 to 16 carbon atoms or an alkenyloxy group having 3 to 16 carbon atoms, A represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and q is Represents 0 or 1. ) The compound represented by
The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains mass%. 4. A compound represented by the general formula (II-a): (In the formula, R ³ and R ⁴ have the same meaning as R ^1. ) and the general formula (II-b): ^5. The liquid crystal composition according to claim 4, containing one kind or two or more kinds of the compounds represented by the formula (wherein R ⁵ and R ⁶ have the same meaning as R ¹ ). 5. Further, the compound represented by the general formula (III): (In the formula, R ⁷ and R ⁸ are each independently an alkyl group or an alkoxyl group having 1 to 16 carbon atoms, or 2 to 16 carbon atoms.
Represents an alkenyl group or an alkenyloxy group having 3 to 16 carbon atoms, A and B are each independently 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4 -Phenylene group, 2,3-difluoro-1,4-phenylene group, 3,5-
Difluoro-1,4-phenylene group, 2,6-difluoro-1,4-phenylene group, 2-methyl-1,4-phenylene group, 3-methyl-1,
4-phenylene group, 2,3-dimethyl-1,4-phenylene group, 3,5
-Dimethyl-1,4-phenylene group, 2,6-dimethyl-1,4-phenylene group or trans-1,4-cyclohexylene group, r and s each independently represent 0 or 1, Z ¹ and Z ²
Are each independently a single bond, -CH ₂ -CH _2- , -CH = CH-, -COO
-Or-OCO- is represented, and X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom or a fluorine atom. 5. The liquid crystal composition according to any one of claims 1 to 4, which contains 5 to 60 mass% of the compound represented by the formula. 6. A compound represented by the general formula (IV): (In the formula, R ⁹ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and B is a 1,4-phenylene group or trans-
It represents a 1,4-cyclohexylene group, X ⁶ represents a cyano group, a fluorine atom, a trifluoromethoxy group or a difluoromethoxy group, and X ⁵ and X ⁷ each independently represent a hydrogen atom or a fluorine atom. 6. The liquid crystal composition according to claim 1, which contains 5 to 40% by mass of the compound represented by the formula (4). 7. A compound represented by the general formula (IV-a): 7. The liquid crystal composition according to claim 6, containing a compound represented by the formula: wherein R ¹⁰ has the same meaning as R ⁹ . 8. A compound represented by the general formula (IV-b): 8. The liquid crystal composition according to claim 6 or 7, containing a compound represented by the formula: wherein R ¹¹ has the same meaning as R ⁹ . 9. A compound represented by the general formula (V): (In the formula, R ¹² and R ¹³ represent an alkyl group or an alkoxyl group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 3 to 7 carbon atoms, and D is 1, 4-phenylene group, 2 or 3-fluoro-1,4-phenylene group, 2,3-difluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene group, 2,6-difluoro- 1,4-phenylene group, 2 or 3-
Methyl-1,4-phenylene group, 2,3-dimethyl-1,4-phenylene group, 3,5-dimethyl-1,4-phenylene group, 2,6-dimethyl-
1,4-phenylene group, trans-1,4-cyclohexylene group, Z ³ is a single bond, -CH2-CH2-, -CH = CH-, -COO-, -OC
Represents O-. 9. The liquid crystal composition according to claim 1, which contains 3 to 30% by mass of the compound represented by 10. A liquid crystal display device using the liquid crystal composition according to claim 1. 11. The twist angle is 180 to 270 °.
10. The liquid crystal display element according to 10.