JP2003013067A - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal composition having a reduced threshold voltage, improved temperature dependency and frequency dependency of the threshold voltage, and high contrast (steepness) display characteristics stable in a wide temperature range. SOLUTION: This liquid crystal composition contains at least one kind or more of compounds represented by formulae I to III (l and n are each 0-10, X<1> is H or F; R<1> is a 2-8C alkyl group or the like; ring A is a group of general formula IV; X<2> and X<3> are each H or F; R<2> and R<3> are each a 1-8C alkyl group or the like which may be substituted with fluorine; rings B, C and D are each a group of formula V; X<4> and X<5> are each H, F or a methyl group; Z<1> and Z<2> are each a single bond, -COO-, -C2 H4 -, -OCH2 -, -CH2 O-, -CH=CH-, -CF=CF'-, -CH=N-N=CH- or -C≡C-; and i and j are each 0 or 1 with the proviso that i+j is 1 or 2), and has 70-180 deg.C phase transition temperature between a nematic phase and an isotropic liquid phase, and 0.06-0.30 refraction index anisotropy.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a nematic liquid crystal composition useful as a liquid crystal display material, and a liquid crystal display device using the nematic liquid crystal composition.

[0002]

2. Description of the Related Art A liquid crystal display device (LCD) has been used as a calculator display, and has been in the same process as the development of computers. From TN-LCD (twisted nematic liquid crystal display device) to STN-LCD. It has responded to the expansion of capacity. STN-L
CDs include Scheffer [SID '85 Digest, 120
Page (1985)], or Kinugawa et al. [SID '86 Digest, 122
Page (1986)], and has begun to spread widely in displays for high information processing such as word processors and personal computers. Recently, an active addressing driving method has been proposed for the purpose of improving the response characteristics of STN-LCD. (Proc. 12th International Display Resea
rch Conference p.503 1992) As a liquid crystal material for this system, the elastic constant ratio K33 / K11 is around 1.5, the dielectric anisotropy Δε and the viscosity are relatively small, and the birefringence Δn is particularly large. Things are required. In addition, as a method capable of performing color display without using a color filter layer, a new reflective color liquid crystal display method utilizing birefringence of liquid crystal and a retardation plate has been proposed. (Technical Report of the Institute of Television Engineers of Japan, vol.14 No10.p.51 1990) As a liquid crystal material for this application, a material that exhibits a larger phase difference due to the difference in the wavelength of light is preferable, and thus the birefringence Δn is particularly large. However, new liquid crystal compounds or liquid crystal compositions are still being proposed. In addition, in a portable terminal display (Personal Digital Assistance), good display characteristics are required in a wider temperature range. As such a liquid crystal material, the viscosity is low, the driving voltage is low, and the driving voltage maintains a constant value over a wide temperature range.
Alternatively, it is required that the drive voltage does not fluctuate within a frequency range corresponding to various time divisions. However, it cannot be said that the response speed and the contrast when incorporated in a display element are sufficient, and new liquid crystal compounds or liquid crystal compositions have been proposed at present.

As described above, one of the important issues for improving the characteristics of TN-LCD and STN-LCD is the improvement of contrast. LCD
In addition to being used indoors, it is increasingly used outdoors in harsh temperature conditions, such as mobile terminal displays for computers, in-vehicle instruments, and displays for measuring instruments used outdoors. I've been Therefore, there is a problem that the display contrast is deteriorated due to the temperature change of the environment where the LCD is placed, and the deterioration of the display quality is caused due to the deterioration of the response speed at low temperature.

There are various factors that cause the deterioration of the LCD display quality due to the ambient temperature change. The cause is the temperature change of the elastic constant and the dielectric constant of the nematic liquid crystal and the temperature change of the intrinsic pitch of the added chiral substance. In order to reduce the temperature change of the threshold voltage Vth to be controlled, the proposal of improving the temperature dependence of the threshold voltage by controlling the temperature change of the intrinsic pitch of the chiral substance (JP-A-55-38869) is already known. ing. However, there have been problems that the effect does not appear due to the combination of the base liquid crystal and the chiral substance and that the display characteristics such as response are adversely affected by increasing the chiral amount.

However, since the current value increases due to the temperature change of the mobility of the ionic substance contained in the liquid crystal, the effective value voltage applied to the liquid crystal is consumed by the ions and the contrast and reliability are deteriorated. There is no known improvement. From this point of view, it is necessary to reduce the amount of the compound having an ester bond that has been widely used in the past, but the increase in the threshold voltage caused thereby has been a problem.

As a technique relating to the general formula (I) which is an essential component of the present invention, Japanese Examined Patent Publication No. 4-501270, JP-A-5-3111724
Japanese Patent Laid-Open No. 6-340877, there is a reduction in threshold voltage, improvement of temperature dependence and frequency dependence, improvement of responsiveness in low temperature range, high contrast ratio in wider temperature range ( The characteristics satisfying the requirements such as steepness closer to 1) have not been obtained.

[0007]

The problem to be solved by the present invention is to provide a highly reliable liquid crystal composition in which the current value is suppressed without deteriorating the liquid crystal characteristics with respect to a low threshold voltage. In addition, the temperature dependence and the frequency dependence of the threshold voltage are further improved, and stable display characteristics having high contrast (steepness) in a wider temperature range are achieved. Specifically, when the threshold voltage Vth is 1.8 V or less,
Temperature dependence of threshold voltage dV / dT (temperature: -20 to 60 ° C) is 2.8 mV /
Frequency dependence of threshold voltage dV / dF (1kHz / 64Hz)
Achieving that the temperature is 1.08 or less at -20 ° C, the steepness (Vsat / Vth) is 1.10 or less (contrast is 4.5 or more), and the panel current value after heating at 80 ° C for 100 hours is 0.12 μA or less. is there. When such a liquid crystal composition is used for a liquid crystal display device, for example, 1/32 to 1/400 Duty, more preferably 1/80
It is possible to provide a liquid crystal display device (STN-LCD) having high contrast, which has an effect of improving characteristics in display of up to 1/250 Duty, and which is more improved with respect to increase in information amount and color display.

[0008]

In order to solve the above problems, the present invention has examined liquid crystal compositions using various liquid crystal compounds. As a result, the following liquid crystal compositions and liquid crystal display devices using the same are obtained. I found it. As the first component, the general formula (I)

[0009]

[Chemical 9]

(Wherein l and n independently represent 0 to 10 and X ¹ represents a hydrogen atom or a fluorine atom), and contains one or more compounds, As a component, the general formula (II)

[0011]

[Chemical 10]

(In the formula, R ¹ represents an alkyl group having 2 to 8 carbon atoms, an alkoxyl group, an alkenyl group or an alkenyloxy group, and ring A is

[0013]

[Chemical 11]

And X ² and X ³ each independently represent a hydrogen atom or a fluorine atom. ) The compound represented by the general formula (III)

[0015]

[Chemical 12]

(In the formula, R ² and R ³ are each independently a fluorine-substituted alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, and an alkyl group having 2 to 8 carbon atoms. Represents an alkenyl group or an alkenyloxy group having 3 to 8 carbon atoms, and ring B, ring C, and ring D are each independently

[0017]

[Chemical 13]

And X ⁴ and X ⁵ each independently represent a hydrogen atom, a fluorine atom or a methyl group, Z ¹ and Z ² each independently represent a single bond, —COO—, —C ₂ H ₄ —, — OCH _2- , -CH ₂ O-, -CH = C
H-, -CF = CF-, -CH = NN = CH- or -C≡C-, i and j each independently represent 0 or 1, and i + j represents 1 or 2. ) Containing one or more compounds represented by,
Moreover, nematic phase-isotropic liquid phase transition temperature (T _NI )
Is 70 ° C. or higher and 180 ° C. or lower, and the anisotropy of refractive index (Δn) is 0.
A liquid crystal composition having a range of 06 to 0.30. Without deteriorating the liquid crystal characteristics for low threshold voltage,
A liquid crystal display device that suppresses a current value, has high reliability, has good temperature dependence and frequency dependence of a threshold voltage, and has stable high contrast (steepness) in a wider temperature range.

The compound of the general formula (I) has a high nematic phase upper limit temperature and a small temperature dependence and frequency dependence of the threshold voltage, but the effect of lowering the threshold voltage is small. Therefore, by using the compound of the general formula (II), which has relatively large dielectric anisotropy and small temperature dependence and frequency dependence of the threshold voltage, it has a low threshold voltage and the temperature dependence of the threshold voltage. And frequency dependence are reduced. Furthermore, by using the compound of the general formula (III) at the same time, it is possible to suppress the current value, to increase the reliability, and to increase the stable contrast in a wide temperature range.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An example of the present invention will be described below.

The first component contains one or more compounds selected from the general formula (I), preferably 1-10, more preferably 1-5. In the formula of the general formula (I), l and n independently represent 0 to 10, X ¹ represents a hydrogen atom or a fluorine atom, and a more preferable form of the general formula (I) is the formula (Ia-1).
~ (Id-1) and formulas (Ia-2) to (Id-2).

[0022]

[Chemical 14]

When only one kind is contained, the formula (Ia-1) or (Ia-2) is preferred when the response speed is important, and the formulas (Ib-1) to (Id-1) are preferred when the contrast is important. ) Or (Ib-2)
~ (Id-2) are preferred. It is particularly effective to contain 2 to 4 kinds of the compound when adjusting the desired refractive index anisotropy, dielectric anisotropy, nematic phase-isotropic liquid phase transition temperature or contrast. , Formulas (Ia-1) to (Id-1), (I
Any combination of -a-2) to (Id-2) is preferable.
General formula (I) and general formula (Ia-1) ~ (Id-1), (Ia-2) ~ (Id
-The content of the compound of 2) is in the range of 5 to 60 mass%,
The range of 40 mass% is preferable, and the range of 5 to 35 mass% is more preferable. The compound selected from the general formula (II) as the second component is 1
One kind or two or more kinds is contained, but three kinds or more are preferable, 3 kinds to 20 kinds are further preferable, and 3 kinds to 15 kinds are particularly preferable.
In the general formula (II), R ¹ represents an alkyl group, an alkoxyl group, an alkenyl group or an alkenyloxy group having 2 to 8 carbon atoms, and an alkyl group or an alkenyl group is preferable. Ring A is

[0024]

[Chemical 15]

Wherein X ² and X ³ independently represent a hydrogen atom or a fluorine atom, and are a general formula (II-a) in which ring A is a cyclohexylene ring or a pyrimidine-2,5-diyl ring. General formula
(II-b) is more preferable.

[0026]

[Chemical 16]

The content of the compounds represented by the general formula (II) and the general formulas (II-a) and (II-b) is in the range of 5 to 60% by mass, preferably 5 to 50% by mass, -40 mass% is more preferred. The third component contains one or more compounds selected from the general formula (III), preferably two or more, and 2 to 20
More preferably, 3 to 15 species are particularly preferable. In the general formula (III), R ² and R ³ are each independently a fluorine-substituted alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, or 2 to 8 carbon atoms. Represents an alkenyl group or an alkenyloxy group having 3 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms,
An alkenyl group having 2 to 6 carbon atoms is more preferable, and formulas (a) to (e) are particularly preferable as the alkyl group or alkenyl group having 1 to 5 carbon atoms.

[0028]

[Chemical 17]

Ring B, Ring C and Ring D are each independently

[0030]

[Chemical 18]

Represents a cyclohexylene ring or
X ⁴ and X ⁵ are preferably a 1.4-phenylene ring represented by a hydrogen atom. Z ^1, Z ² is a single _{bond, -COO -, - C 2 H} 4 -, - CH = CH -, - CF = CF
-Or-C represents C-, but a single bond, -COO-, -C ₂ H ₄ -or
-C≡C- is preferable. i and j are independently 0 or 1, and i + j represents 0 or 1, but i + j = 0 is preferable when the response speed is important, and i + j is i when the nematic liquid crystal range is important. + j = 1 is preferred. A preferred form of general formula (III) is
General formulas (III-a), (III-b), and (III-c).

[0032]

[Chemical 19]

R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, or 2 to 8 carbon atoms. Represents an alkenyl group or an alkenyloxy group having 3 to 8 carbon atoms, X ⁶ , X ⁷ , X ⁸ ,
X ⁹ each independently represent a hydrogen atom, a fluorine atom or a methyl group, Z ³ represents a single bond, -COO- or -C ₂ H ₄ - represents, ring E cyclohexylene ring or 1,4-phenylene ring Represents
p and q represent 0 or 1, and p + q represents 1 or 2 and r is
Represents 0 or 1, and s represents 0 or 1.

In order to achieve high-speed response by reducing the viscosity,
The general formula (III-a) is useful, and the high Δn that accompanies thinner cells
In this case, the general formula (III-b) is useful. General formula (III-a)
Medium, R ⁶, R⁷Are independently alkyl having 1 to 8 carbon atoms.
Group, alkoxyl group having 1 to 8 carbon atoms, 2 to 8 carbon atoms
An alkenyl group or an alkenyloxy having 3 to 8 carbon atoms
Represents a group, especially an alkyl group having 1 to 8 carbon atoms or a carbon
An alkenyl group having 2 to 8 elementary atoms is preferable. p and q are 0 or 1
And p + q is 1 or 2, a nematic phase liquid crystal
When widening the temperature range of the phase, p and q are preferably 1.
When decreasing viscosity, p and q are 0 or 1, and p + q is 1.
Is preferred, p is 1 and q is 0
Is particularly preferable. More preferred form of general formula (III-b)
Are general formulas (III-b-1) to (III-b-7).

[0035]

[Chemical 20]

R¹²~ R^{twenty five}Each independently has 1 to 8 carbon atoms
Alkyl group, C1-8 alkoxyl group, carbon
Alkenyl group having 2 to 8 atoms or alkene group having 3 to 8 carbon atoms
Represents a nyloxy group, an alkyl group having 1 to 8 atoms, carbon
An alkoxyl group having 1 to 8 atoms or an alkyl group having 2 to 8 carbon atoms
Kenyl group is preferred. Z^Four~ Z^TenIs a single bond, -COO- or -C₂H
_Four-Represents. r1 to r7 represent 0 or 1, but a nematic phase liquid crystal
1 is preferred for r1 to r7 for wide phase temperature range.
In order to reduce the viscosity, r1 to r7 are preferably 0.

General formula (III) and general formulas (III-a) to (III-
The content of the compound of c) is in the range of 5 to 70% by mass, but 5 to 6
The range of 0 mass% is preferable, and the range of 5 to 50 mass% is more preferable.

This liquid crystal composition has a nematic phase maximum temperature of
It is characterized by being 70 ° C or higher, preferably 75 ° C or higher, more preferably 80 ° C or higher, particularly preferably 85 ° C or higher. Δn is characterized in the range of 0.06 to 0.30, preferably 0.08 to 0.22, more preferably 0.10 to 0.20, and particularly preferably 0.12 to 0.18 for designing the cell thickness of STN-LCD. The dielectric anisotropy (Δε) may be 1 or more, but is preferably 3 or more and 40 or less. Threshold voltage is 1.5V ~
When 1.9V, the range of 5 ≦ △ ε ≦ 12 is more preferable, when threshold voltage is 1.2V to 1.6V, the range of 8 ≦ △ ε ≦ 16 is more preferable, and when threshold voltage is 0.8V to 1.3V Is more preferably in the range of 12 ≦ Δε ≦ 30.

The liquid crystal composition of the present invention may contain a usual nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a dichroic dye, etc., in addition to the above compounds.

A chiral agent may be added to the liquid crystal composition of the present invention in order to prevent reverse twist domains of TN-LCD and induce a helical structure of STN-LCD. As the chiral agent, a commercially available one can be used. For example, cholesteryl nonanoate (CN), Merck S-
811, R-811, CB-15, C-15 and the like can be mentioned.

The above nematic liquid crystal composition is TN-LCD, STN-
It is useful for LCD, OCB-LCD, polymer dispersion type liquid crystal display element, phase change type cholesteric liquid crystal display element,
Especially useful for STN-LCD. Further, it can be used for a transmissive or reflective liquid crystal display element.

In the STN liquid crystal display device of the present invention, the twist angle can be selected in the range of 180 ° to 270 ° according to the purpose, and 220 ° to 260 ° is preferable. By using the liquid crystal composition of the present invention, the threshold voltage Vth is 1.8V or less, the temperature dependence dV / dT (temperature: -20 to 60 ° C) of the threshold voltage is 2.8 mV / ° C.
Below, the frequency dependence of the threshold voltage dV / dF (1kHz / 64Hz) is -2.
Steepness (Vsat / Vth) is 1.10 or less at 1.08 or less at 0 ℃
A liquid crystal display device having a contrast of 4.5 or more was obtained. Such STN liquid crystal display elements are, for example, 1/60 to 1/4.
In a display of 00 Duty, and more preferably 1/80 to 1/250 Duty, deterioration of display quality due to changes in temperature and frequency is small, and high contrast is provided.

[0043]

The present invention will be described in more detail below with reference to examples, but the present 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. T _NI : Nematic phase-isotropic liquid phase transition temperature (° C) T _{→ N} : Solid phase or smectic phase-nematic phase transition temperature (° C) Vth: When TN-LCD with a cell thickness of 8.3 μm at 25 ° C is constructed ,
Voltage required for 10% change in transmittance (V) Δn: Birefringence (25 ℃)

The STN-LCD display device was manufactured as follows. Chiral substance "S-811" for nematic liquid crystal composition
(Merck) was added to prepare a mixed liquid crystal, and an organic film of `` San Ever 150 '' (Nissan Chemical Co., Ltd.) was rubbed on the opposing flat transparent electrodes to form an alignment film, and a twist angle of 240 degrees STN was formed. -Injected into the cell for LCD display. The chiral substance has a unique helical pitch P of the mixed liquid crystal due to the addition of the chiral substance and a cell thickness d of the display cell of Δnd = 0.90, d / P = 0.50.
Was added.

Vth (STN): Threshold voltage at 25 ° C. (transmittance is 1
Voltage required for 0% change) (V) Vsat (STN): Saturation value voltage at 25 ° C (voltage required for 90% change in transmittance) (V) γ: Steepness at 25 ° C Vsat (STN) / Vth (STN) CR: Contrast when liquid crystal composition is vacuum-injected into STN-LCD with 240 ° twist and driven with 1/200 Duty, 1/16 bias drive waveform Ir: 240 ° twist Current value (μA / cm ² ) after injection of liquid crystal composition into STN-LCD in vacuum for 80 hours at 80 ℃ dV / dT: Temperature dependence of threshold voltage at -20 to 60 ℃ (1kHz, mV / ℃) (Vth (-20 ℃) -Vth (60 ℃)) / 80 dV / dF: Frequency dependence of threshold voltage at -20 ℃ (Vt
h (1kHz) / Vth (64Hz))

The following abbreviations are used in the description of compounds. -n Number: -C _n H _{2n + 1} (Alkyl side chain is a number, and is represented by R.) -On: -OC _n H _{2n + 1} -ndm:-(C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1 ) ndm-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1 --Od (m) n: -O (C _n H _{2n + 1-} CH = CH- (CH ₂ ) _m-2 ) d (m) nO-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-2 O- Linking group -VO-: -COO- -T -: -C≡C- -2-: -CH ₂ CH ₂ --Z-: -CH = NN = CH- Substituent -CN: -C≡N -F: -F Ring Ph: 1,4-phenylene Group Ph1: 3-fluoro-
1,4-phenylene group Ph2: 3,5-difluoro-1,4-phenylene group Cy: 1,4-cyclohexylene group Ma: pyrimidine-
2,5-diyl group

Example 1, Comparative Example 1, Comparative Example 2 A nematic liquid crystal composition No. 1 was prepared and various properties of this composition were measured. The results are shown in Table 1 together with Comparative Example 1.

[0049]

[Table 1]

In Example 1, 0d1-Cy-Cy-Ph2-CN corresponding to the compound of the general formula (Ia), the compound corresponding to the general formula (II-b) and the general formula (III-a), the general formula A liquid crystal composition No. 1 using (III-b) was produced. As a result, compared with Comparative Example 1,
It can be seen that the temperature dependence dV / dT of the threshold voltage shows good characteristics. Also, in the frequency dependence dV / dF of the threshold voltage, the value is closer to 1 at -20 ° C, which shows that the change in the threshold voltage with frequency is small. Further, it can be seen that the current value Ir is also greatly suppressed and the reliability is improved. Further, 0 corresponding to the compound of the general formula (Ia)
In the liquid crystal composition which uses d1-Cy-Cy-Ph2-CN but does not contain the compound corresponding to the general formula (II) (Comparative Example 2), the good temperature dependence of the threshold voltage dV / dT and Although the frequency dependence dV / dF of the threshold voltage has been obtained, the threshold voltage has significantly increased, and the problems cannot be solved at the same time.

(Examples 2 and 3) Further, nematic liquid crystal compositions No. 2 and No. 3 were prepared, and various properties of these compositions were measured.

[0052]

[Table 2]

Examples 2 and 3 simultaneously satisfy the effects of the present invention that they are excellent in temperature dependence at low threshold voltage, excellent frequency dependence, high reliability and high contrast in a wide temperature range. is there.

[0054]

INDUSTRIAL APPLICABILITY The nematic liquid crystal composition of the present invention has good temperature dependence and frequency dependence of the threshold voltage with respect to a low threshold voltage, has stable high contrast in a wider temperature range, and has high reliability. It is possible to achieve high display characteristics. This liquid crystal composition is very useful as STN-LCD.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 19/44 C09K 19/44 19/46 19/46 G02F 1/13 500 G02F 1/13 500

Claims (8)

[Claims] 1. As a first component, a compound represented by the general formula (I): (In the formula, l and n each independently represent 0 to 10, and X ¹ represents a hydrogen atom or a fluorine atom.)
Containing at least one species, the second component is represented by the general formula (II) (In the formula, R ¹ represents an alkyl group having 2 to 8 carbon atoms, an alkoxyl group, an alkenyl group or an alkenyloxy group, and
A is [Chemical 3] And X ² and X ³ each independently represent a hydrogen atom or a fluorine atom. ). The compound containing one or more compounds represented by the general formula (III) (In the formula, R ² and R ³ are each independently a fluorine-substituted alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms or Represents an alkenyloxy group having 3 to 8 carbon atoms, ring B, ring
C and ring D are independently The stands, X ^4, X ⁵ each independently represent a hydrogen atom, a fluorine atom or a methyl group, Z ^1, Z ² are each independently a single bond,
_{-COO -, - C 2 H 4} -, - OCH 2 -, - CH 2 O -, - CH = CH -, - CF = CF -, -
CH = NN = CH- or -C≡C-, where i and j are independent
Represents 0 or 1, and i + j represents 1 or 2. ) Containing one or more compounds represented by, and nematic phase-isotropic liquid phase transition temperature (T _NI ) is 70 ℃ or more 180 ℃ or less, the anisotropy of the refractive index (Δn ) Is in the range of 0.06 to 0.30. 2. The content of the compound of general formula (I) is 5 to 60 mass.
%, And the content of the compound of general formula (II) is 5 to
The content of the compound of the general formula (III) is in the range of 5 to 70% by mass, and the content is in the range of 60% by mass.
The liquid crystal composition described. 3. The general formula (I) is represented by the formulas (Ia-1) to (Id-2): 1. The compound according to claim 1, which is a compound represented by
The liquid crystal composition described. 4. General formula (II) is general formula (II-a) and / or general formula (II-b) (Wherein R ⁴ and R ⁵ each independently represents an alkyl group, an alkoxyl group, an alkenyl group or an alkenyloxy group having 2 to 8 carbon atoms). 4. The liquid crystal composition according to any one of 1 to 3. 5. The general formula (III) is represented by the general formulas (III-a) to (III-c): (In the formula, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, and 2 to 8 carbon atoms. 8 alkenyl group or an alkenyloxy group having 3 to 8 carbon atoms, X ⁶ , X ⁷ , X ⁸ and X ⁹ each independently represent a hydrogen atom, a fluorine atom or a methyl group, and Z ³ is a single bond, -COO- or -C ₂ H ₄ - represents, ring E represents a cyclohexylene ring or 1,4-phenylene ring, p, q are
Represents 0 or 1, and p + q represents 1 or 2, r represents 0 or 1, and s represents 0 or 1. 5. The liquid crystal composition according to claim 2, wherein the liquid crystal composition is selected from the group consisting of: 6. The liquid crystal composition according to claim 1, which has a dielectric anisotropy (Δε) of 3 or more and 40 or less. 7. A liquid crystal display device using the liquid crystal composition according to claim 1. 8. A super twisted nematic (STN) liquid crystal display device using the liquid crystal composition according to claim 1 and having a twist angle of 180 ° to 270 °.