JP2000336364A - Liquid crystal composition and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition causing no decline in both contrast and responsiveness, improved in the temperature dependency of drive voltage along and capable of suppressing electric current levels by combining each specific liquid crystal compounds. SOLUTION: This liquid crystal composition comprises (A) pref. 5-40 wt.% of a 1st component comprising at least one kind of compound of formula I (R1 is a 1-16C alkyl or alkoxyl, 2-16C alkenyl or the like) and (B) pref. 5-40 wt.% of a 2nd component comprising one or more kinds of compound of respective formulas II and III [R2 to R4 are each a (F-substituted) 1-16C alkyl or alkoxyl or the like; rings A to E are each trans-1,4-cyclohexylene or the like; l and m are each 0, 1 or 2; Z1 to Z4 are each a single bond, CH2CH2 or the like; X1 and X3 are each H, F or the like; X2 is cyano, F or the like], being >=75 deg.C in nematic phase upper limit temperature and 0.07-0.18 in refractive index anisotropy (Δn).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nematic liquid crystal composition useful as an electro-optical liquid crystal display material and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Since liquid crystal displays (LCDs) have appeared as calculator displays, they have progressed from computer development to TN-LCDs (twisted nematic liquid crystal displays) to STN-LCDs. It has responded to the expansion of capacity. STN-LCD is based on Scheffer and others [SID '85 D
igest, 120 (1985)] or Kinukawa et al. [SID '86 Di
gest., page 122 (1986)], and has begun to be widely used in displays for high information processing such as word processors and personal computers. Recently, an active addressing drive method has been proposed for the purpose of improving the response characteristics of an STN-LCD. (Proc. 12th International Disp
lay Research Conference p.503 1992) In addition, portable terminal displays (Personal Digital Assistance) require good display characteristics over a wider temperature range. Such a liquid crystal material is required to have a low viscosity, a low driving voltage and a constant value over a wide temperature range, or a driving voltage that does not fluctuate in a frequency range corresponding to various time divisions. I have. However, the response speed and contrast when incorporated into a display element cannot be said to be sufficient, and new liquid crystal compounds or liquid crystal compositions have been proposed at present.

[0003]

As described above, TN-LCD and
One of the important characteristics improvement issues of STN-LCD is to improve the contrast. With the rapid expansion of applications of LCDs, LCDs are not only used indoors, but are also used outdoors where temperature conditions are severe, such as displays for computer portable terminals, in-vehicle instruments, and outdoor measuring instruments. Has increased. The decrease in display contrast due to a change in the temperature of the environment in which the LCD is placed has become a problem. The cause of the deterioration of LCD display quality due to this ambient temperature change is the threshold voltage Vth
Is largely attributable to the temperature dependence.

The cause of the temperature change of the threshold voltage Vth is as follows.
It is conceivable that the temperature change such as the elastic constant and the dielectric constant of the nematic liquid crystal and the temperature change of the specific pitch of the added chiral substance. A proposal for improving the temperature dependency of the threshold voltage by controlling the temperature change of the specific pitch of the chiral substance has already been made (described in JP-A-55-38869). However, depending on the combination of the base liquid crystal and the chiral substance, the effect changes, and by increasing the amount of chiral,
There has been a problem that display characteristics such as response are adversely affected. In addition, 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 is reduced. Is an important factor in improving the contrast.

An object of the present invention is to provide a composition in which the temperature dependence of the driving voltage is improved without lowering the contrast and response, and at the same time, the current value is suppressed. It is to provide a liquid crystal display element using a product.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has examined the liquid crystal compositions using various liquid crystal compounds, and has found the following liquid crystal compositions.

Invention 1 As the first component, general formula (I)

[0008]

[Formula 8]

Wherein R ¹ is an alkyl or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having from 1 to 10), and as a second component, a compound represented by the general formula (II) or (III )

[0010]

[Formula 9]

(Where R^Two, R^Three, R^FourAre independent
In addition, an atom having 1 to 16 carbon atoms which may be
Alkyl or alkoxyl group, C 2 -C 16
Alkenyl group, alkenyloxy group having 3 to 16 carbon atoms,
Or substituted with an alkoxyl group having 1 to 10 carbon atoms
Represents an alkyl group having 1 to 12 carbon atoms, ring A, ring B, ring C,
Ring D and ring E are each independently replaced by a fluorine atom
Optionally substituted 1,4-phenylene group, 2-methyl-1,4-
Phenylene group, 3-methyl-1,4-phenylene group, 2,6-naph
Tylene group, 2,7-phenanthrylene group, 2,7-fluorene
Group, trans-1,4-cyclohexylene group, 2,6-tetrali
Group, 2,6-decalin group, trans-1,3 dioxane-2,5-
Diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-di
Yl, pyrazine-2,5-diyl or pyridazine-2,5-
Represents a diyl group, and l and m are each independently 0, 1 or
Or 2 and Z¹, Z^Two, Z^Three, Z^FourAre, independently of each other,
Single bond, -CH_TwoCH_Two-,-(CH_Two)_Four-, -OCH_Two-, -CH_TwoO- or -C≡C
-Represent, X^TwoIs a cyano group, a fluorine atom, a chlorine atom,
Fluoromethoxy group, trifluoromethyl group, difluoro
Methoxy group, hydrogen atom, 3,3,3-trifluoroethoxy
Represents a group, R ′ or —OR ′, wherein R ′ is a straight chain having 1 to 12 carbon atoms.
Alkyl group or linear alkenyl having 2 to 12 carbon atoms
X¹, X^ThreeIs independently a hydrogen atom,
Represents a fluorine atom or a chlorine atom. However, if ring D is
Midine-2,5-diyl group, m = 0 and Z^FourIs a single bond,
X ¹, X^ThreeIs not simultaneously a fluorine atom, but X^TwoIs R 'or -OR'
To represent X¹, X^ThreeAre not simultaneously hydrogen atoms. From)
Contains one or more selected compounds,
The maximum temperature of the nematic phase is 75 ° C or higher, and
Characterized in that the anisotropy (Δn) is in the range of 0.07 to 0.18
Liquid crystal composition.

Invention 2. As the first component, one or more compounds of the general formula (I) are contained, and the content is 5 to 40.
% By weight, and as a second component, a general formula (II):
The liquid crystal composition according to Invention 1, wherein the liquid crystal composition contains one or more selected from compounds of the general formula (III), and the content of each of the selected compounds is in the range of 5 to 40% by weight. object.

Invention 3 As the compound of the general formula (II), Ring A and Ring B are trans-1,4-cyclohexylene groups,
General formula (II-a) in which Z ¹ and Z ² are single bonds

[0014]

[Formula 10]

(Wherein, R ⁵ and R ⁶ have the same meanings as R ² and R ³ , ring F represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and n represents , 0 or 1.) The liquid crystal composition according to invention 1 or 2, comprising one or more compounds selected from the group consisting of:

Invention 4. As the first component, one or more compounds of the general formula (I) are contained, and the content thereof is 5 to 4
In the range of 0% by weight and as the second component, the compound represented by the general formula (II-
3. The liquid crystal composition according to Invention 3, wherein the liquid crystal composition contains one or more kinds of the compound (a), and the content thereof is in the range of 5 to 40% by weight.

Invention 5 As a compound of the general formula (III), ring D
Is a trans-1,4-cyclohexylene group, Z ³ and Z ⁴ are a single bond, and m = 1 is a general formula (III-a)

[0018]

[Formula 11]

(Wherein R ⁷ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms;
Represents a 1,4-phenylene group or trans-1,4-cyclohexylene group, X ⁵ represents a cyano group, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, X ⁴ ,
X ⁶ each independently represents a hydrogen atom or a fluorine atom. 3. The liquid crystal composition according to the invention 1 or 2, comprising one or more compounds selected from the group consisting of:

Invention 6 As the first component, one or more compounds of the general formula (I) are contained, and the content thereof is 5 to 4
In the range of 0% by weight, and containing one or more compounds of the general formula (III-a), the content of the invention 5 characterized in that the content is in the range of 5 to 40% by weight Liquid crystal composition.

Invention 7 One or more compounds of the general formula (I) are contained, the content of which is in the range of 5 to 40% by weight, and the compound of the general formula (II-b)

[0022]

Embedded image

Wherein R ⁸ and R ⁹ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. Containing the above compound, the content of which is in the range of 5 to 40% by weight, further represented by the general formula (II-c)

[0024]

Embedded image

(Wherein R ¹⁰ and R ¹¹ are each independently:
Represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. 7.) The liquid crystal composition according to any one of inventions 1 to 6, comprising one or more compounds selected from the group consisting of (1) and (2), and the content thereof is in the range of 5 to 40% by weight.

Invention 8. As the general formula (III) or (III-a), the general formula (III-b)

[0027]

Embedded image

Wherein R ¹² represents one or more compounds selected from the group consisting of an alkyl group having 1 to 16 carbon atoms and an alkenyl group having 2 to 8 carbon atoms. The invention characterized in that the content is in the range of 5 to 40% by weight.
8. The liquid crystal composition according to 1 to 7.

Invention 9 A liquid crystal display device using the liquid crystal composition according to any one of Inventions 1 to 8.

Invention 10 A super-twisted nematic (STN) liquid crystal display device using the liquid crystal composition according to any one of Inventions 1 to 8, having a twist angle of 220 ° to 270 °.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described below.

In the invention 1, the first component contains one or more compounds selected from the general formula (I), and one or two compounds are preferable. In the formula, R1 is an alkyl group or alkoxyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or an alkoxyl group having 1 to 10 carbon atoms. Represents an alkyl group having 1 to 12 carbon atoms substituted with, an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms is preferable, an alkyl group having 1 to 8 carbon atoms, An alkenyl group having 2 to 8 atoms is more preferable, and 1
RCH2 = CH2- as an alkyl group or alkenyl group of
(CH2) o (R = H, CH3-, CH3CH2CH2-, o = 0, 2) is particularly preferred. Further, as a second component, contains one or more compounds selected from the general formulas (II) and (III),
Or more are preferable, 3 to 20 are more preferable, and 5 to
15 types are particularly preferable, and it is more preferable that at least 2 types of the compound of the general formula (II) are contained therein. This liquid crystal composition is characterized in that the maximum temperature of the nematic phase is 75 ° C. or higher, preferably 80 ° C. or higher, particularly preferably 85 ° C. or higher. Also, Δn is in the range of 0.07 to 0.18, preferably 0.08 to 0.17. R ² , R ³ , and R ⁴ each independently may have 1 to 1 carbon atoms which may be substituted by fluorine.
6 alkyl or alkoxyl groups, 2 to 16 carbon atoms
Represents an alkenyl group, an alkenyloxy group having 3 to 16 carbon atoms, or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxyl group having 1 to 10 carbon atoms, but an alkyl group having 1 to 16 carbon atoms. Group, an alkenyl group having 2 to 16 carbon atoms is preferable, an alkyl group having 1 to 8 carbon atoms,
2 to 8 alkenyl groups are more preferable, and RCH ₂も し く は CH _2- (CH ₂ ) _o (R = H, CH
_3- , CH ₃ CH ₂ CH _2- , o = 0, 2) are particularly preferred. Ring A, Ring B,
Ring C, ring D and ring E are each independently a 1,4-phenylene group optionally substituted by a fluorine atom, 2-methyl-1,4
-Phenylene group, 3-methyl-1,4-phenylene group, 2,6-naphthylene group, 2,7-phenanthrylene group, 2,7-fluorene group, trans-1,4-cyclohexylene group, 2,6- Tetralin group, 2,6-decalin group, trans-1,3 dioxane-2,5-
Diyl, pyridine-2,5-diyl, pyrimidine-2,5-diyl, pyrazine-2,5-diyl or pyridazine-2,5-
Represents a diyl group, but a 1,4-phenylene group, trans-1,4-
A cyclohexylene group is preferable, and in rings A, B, D, and E, a trans-1,4-cyclohexylene group is more preferable,
In ring C, a 1,4-phenylene group is more preferable. l and m each independently represent 0, 1 or 2, but 0 or 1
Is preferred. ^{Z 1, Z 2, Z 3} , Z 4 are each independently a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH 2 -, - CH 2 O- or -C≡C- As shown, Z ¹ and Z ² are preferably a single bond or —CH ₂ CH ₂ —, and more preferably a single bond. In Z ³ and Z ⁴ , a single bond or —C≡C— is preferable, and a single bond is more preferable. X ²
Represents a cyano group, a fluorine atom, a chlorine atom, a trifluoromethoxy group, a trifluoromethyl group, a difluoromethoxy group, a hydrogen atom, a 3,3,3-trifluoroethoxy group, R 'or -OR', and R 'is Represents a linear alkyl group having 1 to 12 carbon atoms or a linear alkenyl group having 2 to 12 carbon atoms, preferably a cyano group, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, and a fluorine atom, trifluoromethoxy And a difluoromethoxy group are more preferred, and a fluorine atom is particularly preferred. X ¹ and X ³ represent a hydrogen atom, a fluorine atom or a chlorine atom, preferably a hydrogen atom or a fluorine atom, particularly preferably a fluorine atom.

In the invention 2, the content of each compound is from 5 to 40.
%, Preferably from 5 to 25% by weight, particularly preferably from 5 to 15% by weight.

In the invention 4, the compound of the general formula (I) is
One or two or more of the compounds of the general formula (II-a)
The compound contains at least one species and the content is in the range of 5 to 40% by weight, but the compound of the general formula (I) may contain one or two kinds and the content is in the range of 5 to 15% by weight. Preferably, two or more compounds of the general formula (II-a) are contained and the content is preferably in the range of 5 to 15% by weight.

In the invention 6, the compound of the general formula (I) is
Contains at least two species, the content of which is 5-40% by weight
Contains, as a second component, one or more compounds of the general formula (III-a), the content of which is 5 to 4
Although it is in the range of 0% by weight, it is preferable that one or two compounds of the general formula (I) are contained and the content thereof is in the range of 5 to 15% by weight, and the compound of the general formula (III-a) Is preferably contained in an amount of 5 to 15% by weight.

In the invention 7, the compound of the general formula (I) is
Contains at least two species, the content of which is 5-40% by weight
Contains one or more compounds selected from the general formula (II-b), and the content is 5 to 40% by weight.
%, Further contains one or more compounds selected from the general formula (II-c), the content of which is in the range of 5 to 40% by weight, the general formula (II-b), 5 to 1 compounds of (II-c)
It is preferable that five types be contained and the content be in the range of 5 to 15% by weight. In the formula, R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and an alkyl group or alkenyl group having 1 to 5 carbon atoms. RCH ₂ = CH _2- (CH ₂ ) _o (R = H, CH _3- , CH ₃ CH ₂ CH
_2- , o = 0, 2) are particularly preferred.

In the invention 8, the general formula (III) described in the invention 1
Or, as the general formula (III-a), contains one or more compounds selected from the general formula (III-b) and the content thereof is
In the range of 5 to 40% by weight, the compound of the general formula (III-b)
Preferably, the content is in the range of 5 to 15% by weight, more preferably 1 to 10 types. In the formula, R ¹² represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and RCH ₂ CHCH ₂ — (CH ₂ ) _o (1 to 5 alkyl groups or alkenyl groups) R = H, CH _3- , CH ₃ CH ₂ CH _2- , o = 0,
2) is particularly preferred.

The above nematic liquid crystal composition is TN-LCD or STN-
Useful for LCDs, but especially useful for STN-LCDs. Further, it can be used for a transmissive or reflective liquid crystal display device. The liquid crystal composition of the present invention has the general formulas (I) to (VII)
In addition to the compounds represented by I), ordinary nematic liquid crystals,
It may contain a smectic liquid crystal, a cholesteric liquid crystal, or the like.

[0039]

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. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by weight”.

The characteristics measured in the examples are as follows.

T _NI ： Nematic phase-isotropic liquid phase transition temperature (℃) T → _N : Solid phase or smectic phase-nematic phase transition temperature (° C) Vth: Threshold voltage (V) when a TN-LCD having a cell thickness of 6 μm is formed Δε: Dielectric anisotropy Δn: Birefringence η: 20 ° C Viscosity (mPa Kis) Ir: 240 ° twist STN-LCD, liquid crystal composition is vacuum-injected, current value after heating at 80 ° C for 100 hours (μA / cm ² ) CR: 240 ° twist STN- Contrast when liquid crystal composition is vacuum-injected into LCD and driven with 1/200 duty, 1/16 bias drive waveform.

The production of the STN-LCD display element was performed as follows. Chiral substance "S-811" in nematic liquid crystal composition
(Merck) was added to prepare a mixed liquid crystal, and “Sanever 610” (manufactured by Nissan Chemical Industries) was placed on the opposing flat transparent electrode.
Twist angle of 24 after rubbing the organic film
It was injected into a 0 degree STN-LCD display cell. Note that the chiral substance is such that the specific helical pitch P of the mixed liquid crystal due to the addition of the chiral substance and the cell thickness d of the display cell are Δn · d = 0.85, d / P = 0.5
It was added so as to be 0.

The following abbreviations are used in describing the compounds.

Terminal n (number) C _n H _{2n + 1} -C trans-1,4-cyclohexylene group C / 1,4-cyclohexenediyl group P 1,4 phenylene group Pm pyrimidine-2,5-diyl group E -COO- e -OCO- A -CH ₂ CH ₂ -t -C≡C- CN -C≡N On -OC _n H _{2n + 1} F -F f F atom bound to the ortho position of the terminal group ndm- C _n H _{2n + 1} -C = C- (CH ₂ ) _m-1 --O (dm) n -O (CH2) m-2-C = C-CnH2n + 1 (Example 1, Comparative Example 1) Nematic liquid crystal composition No.1

[0045]

Embedded image

Table 1 shows the results of measuring various properties of this composition together with Comparative Example 1.

[0047]

[Table 1] As shown in Table 1, the liquid crystal composition of Example 1 significantly suppressed the current value and improved the contrast as compared with the composition of Comparative Example 1. Using the TN-LCD fabricated here, the temperature dependence of the electro-optical characteristics at -10 ° C to 60 ° C was measured, and a liquid crystal display device with excellent display characteristics of 1.4 mV / ° C was produced. Was.

Example 2 A nematic liquid crystal composition No. 2 was prepared (Example 2), and its various characteristics were measured. As a comparative composition, the composition and characteristic data of a composition other than the present invention (comparative) The results are shown in Table 2 together with Example 2).

[0049]

[Table 2]

As shown in Table 2, the liquid crystal composition of Example 2 also significantly suppressed the current value as compared with the composition of Comparative Example 2,
The drive voltage has also improved.

The temperature dependence of the electro-optical characteristics at -10 ° C. to 60 ° C. was measured using the TN-LCD fabricated here.
A liquid crystal display device exhibiting excellent display characteristics of mV / ° C. was produced. Example 3 Nematic liquid crystal compositions Nos. 3 to 5 were prepared, and the composition and characteristic data are shown in Table 3.

[0052]

[Table 3]

Also from these compositions, a liquid crystal display device having excellent temperature dependency and low current value could be produced.

[0054]

By the combination of the liquid crystal materials of the present invention, a liquid crystal composition having a suppressed current value and a high dielectric anisotropy was obtained. When this composition was used for a liquid crystal display device, the threshold voltage was low and the temperature characteristics were excellent. This liquid crystal display is very practical as STN and TN-LCD.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G02F 1/13 500 G02F 1/13 500 F term (Reference) 4H027 BA01 BB04 BD23 BE05 CB01 CE04 CL01 CM01 CM04 CN01 CN04 CQ02 CQ04 CT01 CT02 CT03 CT04 CU04 CW02 DE04 DP01

Claims (10)

[Claims] 1. A compound represented by the following general formula (I):(Where R¹Is an alkyl group having 1 to 16 carbon atoms or
Lucoxyl group, alkenyl group having 2 to 16 carbon atoms, carbon
An alkenyloxy group having 3 to 16 atoms, or 1 carbon atom
1 to 12 carbon atoms substituted with an alkoxyl group
Represents an alkyl group. One or more compounds selected from
Contains two or more kinds, and as the second component, the general formulas (II) and (II)
I)(Where R^Two, R^Three, R^FourAre each independently fluorine-substituted
An alkyl group having 1 to 16 carbon atoms which may be
Alkoxyl group, alkenyl group having 2 to 16 carbon atoms, carbon
An alkenyloxy group having 3 to 16 atoms, or carbon atom
1 to 12 carbon atoms substituted with an alkoxyl group of 1 to 10
A ring A, ring B, ring C, ring D and ring E,
Even if each is independently substituted by a fluorine atom
Good 1,4-phenylene group, 2-methyl-1,4-phenylene group, 3
-Methyl-1,4-phenylene group, 2,6-naphthylene group, 2,7-phenyl
Enanthrylene group, 2,7-fluorene group, trans-1,4-
Cyclohexylene group, 2,6-tetralin group, 2,6-decalin
Group, trans-1,3 dioxane-2,5-diyl group, pyridine-
2,5-diyl group, pyrimidine-2,5-diyl group, pyrazine-2,
Represents a 5-diyl group or a pyridazine-2,5-diyl group, l,
m independently represents 0, 1 or 2; Z¹,
Z^Two, Z^Three, Z^FourIs independently a single bond, -CH_TwoCH_Two-,-
(CH_Two)_Four-, -OCH_Two-, -CH_TwoO- or -C≡C- stands for X^TwoIs cyano
Group, fluorine atom, chlorine atom, trifluoromethoxy group,
Trifluoromethyl group, difluoromethoxy group, hydrogen atom
, A 3,3,3-trifluoroethoxy group, R 'or -OR'
R ′ is a linear alkyl group having 1 to 12 carbon atoms or carbon
Represents a linear alkenyl group having 2 to 12 elementary atoms, X¹, X
^ThreeIs independently a hydrogen atom, a fluorine atom or
Represents a chlorine atom. Provided that ring D is pyrimidine-2,5-diyl
Group, m = 0 and Z^FourIs a single bond, X ¹, X^ThreeAt the same time
X, not nitrogen atom^TwoRepresents R 'or -OR', X¹,
X^ThreeAre not simultaneously hydrogen atoms. )
Contains 1 or 2 or more types, and on the nematic phase
The limiting temperature is 75 ° C or higher and the refractive index anisotropy (Δn) is 0.0
A liquid crystal composition characterized by being in the range of 7 to 0.18. 2. A compound of the general formula (I) as a first component
Contains at least two species, the content of which is 5-40% by weight
In the range, further as a second component, a general formula (II), a general formula
The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more kinds selected from the compounds of (III), and the content of each of the selected compounds is in the range of 5 to 40% by weight. . 3. The compound of the general formula (II) wherein Ring A and Ring B are trans-1,4-cyclohexylene groups, Z ¹ , Z ²
Is a single bond of the general formula (II-a) (Wherein, R ⁵ and R ⁶ represent the same meaning as R ² and R ^3, and ring F is
Represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group, and n represents 0 or 1. 1) selected from
3. The liquid crystal composition according to claim 1, wherein the liquid crystal composition contains one or more compounds. 4. The composition according to claim 1, wherein the first component comprises one or more compounds of the general formula (I) in a content of 5 to 40% by weight, and the second component comprises a compound of the general formula (I) II-a)
Contains one or more compounds, and the content is
4. The liquid crystal composition according to claim 3, wherein the content is in the range of 5 to 40% by weight. 5. A compound of the general formula (III-a) wherein ring D is a trans-1,4-cyclohexylene group, Z ³ and Z ⁴ are single bonds, and m = 1. ) (Wherein, R ⁷ represents an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and ring G is a 1,4-phenylene group or a trans-1,4-cyclohexylene group X ⁵ represents a cyano group, a fluorine atom, a trifluoromethoxy group, or a difluoromethoxy group, and X ⁴ and X ⁶ each independently represent a hydrogen atom or a fluorine atom.) 3. The liquid crystal composition according to claim 1, further comprising two or more compounds. 6. A compound comprising one or more compounds of the general formula (I) as a first component, the content of which is in the range of 5 to 40% by weight and the compound of the general formula (III-a) 6. The liquid crystal composition according to claim 5, comprising one or more compounds, and the content is in the range of 5 to 40% by weight. 7. A compound containing one or more compounds of the general formula (I) in a content of from 5 to 40% by weight and a compound of the general formula (II-b) (Wherein, R ⁸ and R ⁹ each independently represent 1 to 8 carbon atoms.
Represents an alkyl group or an alkenyl group having 2 to 8 carbon atoms. ) Containing one or two or more compounds selected from the group consisting of a compound represented by the general formula (I)
Ic) (Wherein, R ¹⁰ and R ¹¹ each independently represent 1 carbon atom
Represents an alkyl group having up to 8 or an alkenyl group having 2 to 8 carbon atoms. 7. The liquid crystal composition according to claim 1, comprising one or more compounds selected from the group consisting of (1) and (2), and the content thereof is in the range of 5 to 40% by weight. 8. A compound of the general formula (III-b) represented by the general formula (III) or (III-a): (In the formula, R ¹² represents an alkyl group having 1 to 16 carbon atoms or an alkenyl group having 2 to 8 carbon atoms.)
Contains two or more compounds, the content of which is 5 to
8. The liquid crystal composition according to claim 1, wherein the content is in a range of 40% by weight. 9. A liquid crystal display device using the liquid crystal composition according to claim 1. 10. A super twisted nematic (STN) liquid crystal display device using the liquid crystal composition according to claim 1 and having a twist angle of 220 ° to 270 °.