JP6024950B2 - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to a nematic liquid crystal composition having a negative dielectric anisotropy (Δε) useful as a liquid crystal display material, and a liquid crystal display device using the same.

  Liquid crystal display elements are used in various electric appliances for home use, measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions, etc., including watches and calculators. Typical liquid crystal display methods include TN (twisted nematic), STN (super twisted nematic), DS (dynamic light scattering), GH (guest / host), and IPS (in-plane switching). Type, OCB (optical compensation birefringence) type, ECB (voltage controlled birefringence) type, VA (vertical alignment) type, CSH (color super homeotropic) type, FLC (ferroelectric liquid crystal), etc. . Examples of the driving method include static driving, multiplex driving, simple matrix method, active matrix (AM) method driven by TFT (thin film transistor), TFD (thin film diode), and the like.

  In these display methods, the IPS type, ECB type, VA type, CSH type, and the like have a feature that a liquid crystal composition having a negative value of Δε is used. Among these, the VA type display method by AM driving is used for a display element that requires a high speed response and a wide viewing angle, such as a television.

  As a liquid crystal composition having a negative Δε, a liquid crystal composition using the following liquid crystal compounds (A) and (B) having a 2,3-difluorophenylene skeleton (see Patent Document 1) is disclosed.

  In this liquid crystal composition, liquid crystal compounds (C) and (D) are used as the liquid crystal compound having Δε of approximately 0. However, in a liquid crystal composition that requires a high-speed response such as a liquid crystal television, the liquid crystal composition has a sufficiently low viscosity. It has not been realized.

  On the other hand, a liquid crystal composition using the liquid crystal compound (E) has already been disclosed, but a liquid crystal composition having a small refractive index anisotropy Δn in combination with the liquid crystal compound (D) (see Patent Document 2) and response. A liquid crystal composition to which a liquid crystal compound (F) is added for improving the speed (see Patent Document 3) has been introduced.

  In addition, a liquid crystal composition using the liquid crystal compound (G) and the liquid crystal compound (F) has already been disclosed (see Patent Document 4), but further high-speed response is required.

A liquid crystal composition (see Patent Document 5) in which the liquid crystal compound (A) and the liquid crystal compound (G) are combined with a liquid crystal compound represented by the formula (I) in which Δε is substantially zero is disclosed. However, in the manufacturing process of the liquid crystal display element, it was thought that the compound having a low vapor pressure volatilizes because the liquid crystal composition is injected into the liquid crystal cell, so that the content cannot be increased. . For this reason, the liquid crystal composition has a problem that the content of the liquid crystal compound represented by the formula (I) is limited and the viscosity is remarkably high although it exhibits a large Δn.

Further, Patent Documents 6 and 7 have already disclosed liquid crystal compositions using a compound having a fluorine-substituted terphenyl structure.
On the other hand, Patent Document 8 discloses that the response speed of a homeotropic liquid crystal cell is improved by using a liquid crystal material having a large index represented by (Equation 1), but this is not sufficient.

From the above, in a liquid crystal composition that requires a high-speed response such as a liquid crystal television, without reducing the refractive index anisotropy (Δn) and nematic phase-isotropic liquid phase transition temperature (T _ni ), It has been demanded that the viscosity (η) is sufficiently small, the rotational viscosity (γ1) is sufficiently small, and the elastic constant (K ₃₃ ) is large.

JP-A-8-104869 European Patent Application No. 0474402 JP 2006-37054 A JP 2001-354967 A WO2007 / 077872 JP 2003-327965 A WO2007 / 077872-301643 JP 2006-301643 A

The problem to be solved by the present invention is that the viscosity (η) is sufficiently small without reducing the refractive index anisotropy (Δn) and the nematic phase-isotropic liquid phase transition temperature (T _ni ), and the rotational viscosity Provided is a liquid crystal composition having a negative Δε having a sufficiently small (γ1), a large elastic constant (K ₃₃ ), and a large absolute value, and further having an excellent response speed of a display quality such as a VA type using the liquid crystal composition. The object is to provide a fast liquid crystal display element.

  The present inventor has studied various azine derivatives and fluorobenzene derivatives, and found that the above problem can be solved by combining specific compounds, and has completed the present invention.

  In the present invention, the first component is represented by the general formula (I)

Wherein R ¹¹ and R ¹² are each independently an 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 an alkenyloxyl group having 2 to 8 carbon atoms. X ¹¹ , X ¹² , X ¹³ , X ¹⁴ , X ¹⁵ , X ¹⁶ , X ¹⁷ and X ¹⁸ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom. 2 or more types, the content is 3% to 45% by mass, and the second component contains one or more liquid crystal compounds having a negative Δε having an absolute value of 3 or more. A liquid crystal composition is provided, and a liquid crystal display device using the same is provided.

The liquid crystal composition of the present invention, without reducing the Δn and T _ni, eta is sufficiently small, .gamma.1 is sufficiently small, those K ₃₃ is large, the display quality of a VA liquid or the like by the use of this An excellent liquid crystal display element with a high response speed can be provided.

  The liquid crystal composition of the present invention contains one or more compounds represented by the general formula (I), which is an azine derivative, as a first component, and the content thereof is 3% by mass to 45% by mass. Is more preferably 5% by mass to 30% by mass, and particularly preferably 10% by mass to 25% by mass. More specifically, in order to obtain high Δn, the content is preferably 20% by mass to 45% by mass. However, when emphasizing the suppression of precipitation at low temperature, the content is 3% by mass to 20% by mass. % Is preferred.

  The general formula (I) is preferably the general formula (IA).

In the formula, R ¹³ represents an 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 an alkenyloxyl group having 2 to 8 carbon atoms, but R ¹³ represents carbon. An alkenyl group having 2 to 8 is more preferable. More specifically, a compound represented by the formula (I-A1) or (I-A2) is particularly preferable.

  The liquid crystal composition of the present invention contains one or more liquid crystal compounds having a negative Δε having an absolute value of 3 or more as the second component, but having a negative dielectric constant having an absolute value of 4 or more. It is more preferable to include a liquid crystal compound having anisotropy, and it is particularly preferable to include a liquid crystal compound having a negative dielectric anisotropy having an absolute value of 5 or more. The dielectric anisotropy (Δε) of the liquid crystal compound was prepared by adding 10% by mass of a liquid crystal compound to the liquid crystal composition having a dielectric anisotropy of about 0 at 25 ° C. It was determined by extrapolation from the measured value of dielectric anisotropy (Δε) of the object.

  Although the liquid-crystal composition of this invention contains 1 type, or 2 or more types of 2nd components, it is preferable to contain 1 type to 15 types, and it is still more preferable to contain 2 types to 10 types.

  The content of the second component is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, and particularly preferably 30% by mass to 70% by mass.

  The second component is preferably a compound represented by general formulas (II-A) and (II-B).

In the formula, each of R ¹ and R ² independently represents an 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 an alkenyloxyl group having 2 to 8 carbon atoms. It represents, ^{R 1} and ^R present in the ² one -CH ₂ - or nonadjacent two or more -CH ₂ - may be replaced each independently -O- and / or -S- In addition, one or two or more hydrogen atoms present in R ¹ and R ² may be each independently substituted with a fluorine atom or a chlorine atom. Ring A and Ring B are each independently a trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene group, 2,3-difluoro-1,4-phenylene group, 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, A piperidine-1,4-diyl group, a naphthalene-2,6-diyl group, a decahydronaphthalene-2,6-diyl group or a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group is represented. p and q each independently represents 0, 1 or 2.

R ¹ and R ² in the formula are each independently a linear alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a group having 2 to 5 carbon atoms. More preferably, it is an alkenyloxyl group. More specifically, in order to increase the elastic constant (K ₃₃ ), R ¹ is more preferably an alkenyl group having 2 to 5 carbon atoms.

  In the formula, ring A and ring B are each independently a trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4- A phenylene group, a 3,5-difluoro-1,4-phenylene group, or a 2,3-difluoro-1,4-phenylene group is more preferable, and a trans-1,4-cyclohexylene group or 1,4- A phenylene group is particularly preferred.

  More preferably, p and q in the formula are each independently 0 or 1.

  The compound represented by the general formula (II-A) is more preferably a compound represented by the general formula (II-A1) or (II-A2), and is represented by the general formula (II-B). The compound is more preferably general formula (II-B1).

In the formula, R ³ and R ⁴ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and one or more hydrogen atoms present in R ³ and R ⁴ Each atom may be independently substituted with a fluorine atom.

More preferably, R ³ and R ⁴ in the formula are each independently a linear alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms. More specifically, in order to increase the elastic constant (K ₃₃ ), it is particularly preferable that one of R ³ and R ⁴ is an alkenyl group having 2 to 5 carbon atoms.

  The liquid crystal composition of the present invention further contains one or more compounds selected from the compound group represented by formulas (III-A) to (III-J) as a third component. However, it may further contain 1 to 10 compounds selected from general formulas (III-A), (III-D), (III-F), (III-G) and (III-H). preferable.

In the formula, R ⁵ is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, R ⁶ is an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, and 2 to 5 carbon atoms. Or an alkenyloxyl group having 2 to 5 carbon atoms. In the general formula (III-A), R ⁵ is more preferably an alkenyl group having 2 to 5 carbon atoms, and R ⁶ is an alkyl group having 1 to 5 carbon atoms.

  As a further component, you may contain the compound represented by general formula (V) 1 type (s) or 2 or more types.

In the formula, each of R ²¹ and R ²² independently represents an 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 an alkenyloxyl group having 2 to 8 carbon atoms. As shown, an alkyl group having 1 to 5 carbon atoms and an alkenyl group having 4 to 8 carbon atoms are more preferable.

  The liquid crystal composition of the present invention preferably contains a compound represented by general formula (I), general formula (II-A1) and general formula (II-A2) at the same time. It is more preferable that the compounds represented by (II-A1), general formula (II-A2) and general formula (III-A) are simultaneously contained. It is also preferable to contain the compounds represented by general formula (I), general formula (II-A1), general formula (II-A2) and general formula (II-B1) at the same time. It is further preferable that the compounds represented by (II-A1), general formula (II-A2), general formula (II-B1) and general formula (III-A) are simultaneously contained. Further, it is particularly preferable that the compounds represented by the general formula (I), the general formula (II-A1), the general formula (II-A2), the general formula (III-A), and the general formula (V) are simultaneously contained. .

  The liquid crystal composition of the present invention has a dielectric anisotropy (Δε) at 25 ° C. of −2.0 to −8.0, preferably −2.0 to −6.0, and −2.0 to -5.0 is more preferable, and -2.5 to -4.0 is particularly preferable.

  The liquid crystal composition of the present invention has a refractive index anisotropy (Δn) at 20 ° C. of 0.08 to 0.14, more preferably 0.09 to 0.13, and 0.09 to 0.12. Particularly preferred. More specifically, it is preferably 0.10 to 0.13 when dealing with a thin cell gap, and preferably 0.08 to 0.10 when dealing with a thick cell gap.

  The liquid crystal composition of the present invention has a viscosity (η) at 20 ° C. of 10 to 30 mPa · s, more preferably 10 to 25 mPa · s, and particularly preferably 10 to 22 mPa · s.

  The liquid crystal composition of the present invention has a rotational viscosity (γ1) at 20 ° C. of 60 to 130 mPa · s, more preferably 60 to 110 mPa · s, and particularly preferably 60 to 100 mPa · s.

The liquid crystal composition of the present invention has a nematic phase-isotropic liquid phase transition temperature (T _ni ) of 60 ° C to 120 ° C, more preferably 70 ° C to 100 ° C, and particularly preferably 70 ° C to 85 ° C.

  The liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, an antioxidant, an ultraviolet absorber, a polymerizable monomer and the like in addition to the above-described compounds.

  For example, a polymerizable compound such as a biphenyl derivative or a terphenyl derivative is contained as a polymerizable monomer, and the content is preferably 0.01% to 2%. More specifically, the liquid crystal composition of the present invention has the general formula (IV).

It is preferable to contain 1 type, or 2 or more types of the polymerizable monomer represented by these.
In the formula, R ⁷ and R ⁸ are each independently the following formulas (R-1) to (R-15):

X ¹ to X ⁸ each independently represents a trifluoromethyl group, a trifluoromethoxy group, a fluorine atom or a hydrogen atom.

  The structure of the biphenyl skeleton in the general formula (IV) is more preferably the formula (IV-11) to the formula (IV-14), and particularly preferably the formula (IV-11).

  The polymerizable compound containing a skeleton represented by the formulas (IV-11) to (IV-14) has an optimum alignment regulating force after polymerization, and a good alignment state is obtained.

For example, a polymerizable compound-containing liquid crystal composition containing formula (I), general formula (II-A1), (II-A2), general formula (III-A) and general formula (IV) simultaneously has a low viscosity (η ), A low rotational viscosity (γ1) and a large elastic constant (K ₃₃ ) are achieved. Therefore, a PSA mode or PSVA mode liquid crystal display device using the same can achieve a high-speed response.

  The liquid crystal display device using the liquid crystal composition of the present invention has a remarkable feature of high-speed response, and is particularly useful for a liquid crystal display device for driving an active matrix. Or it can be applied for ECB mode.

EXAMPLES The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.
The following abbreviations are used for the description of compounds in the examples.
(Side chain)
-n -C _n H _{2n + 1} linear alkyl group with n carbon atoms
n- C _n H _{2n + 1-} linear alkyl group with n carbon atoms
-On -OC _n H _{2n + 1} linear alkoxyl group with n carbon atoms
nO- C _n H _{2n + 1} O- Linear alkoxyl group with n carbon atoms
-V -CH = CH ₂
V- CH ₂ = CH-
-V1 -CH = CH-CH ₃
1V- CH ₃ -CH = CH-
-2V -CH ₂ -CH ₂ -CH = CH ₃
V2- CH ₃ = CH-CH ₂ -CH _2-
-2V1 -CH ₂ -CH ₂ -CH = CH-CH ₃
1V2- CH ₃ -CH = CH-CH ₂ -CH _2-
-T- -C≡C-
-Az- -C = NN = C-

(Ring structure)

  In the examples, the measured characteristics are as follows.

T _ni : Nematic phase-isotropic liquid phase transition temperature (° C.)
Δn: refractive index anisotropy at 20 ° C. Δε: dielectric anisotropy at 25 ° C. η: viscosity at 20 ° C. (mPa · s)
γ1: rotational viscosity at 20 ° C. (mPa · s)
K ₃₃ : Elastic constant at 20 ° C. K ₃₃ (pN)
(Comparative Examples 1 and 2 and Examples 1, 2, and 3)
LC-A (Comparative Example 1), LC-B (Comparative Example 2), LC-1 (Example 1), LC-2 (Example 2) and LC-3 (Examples) having the compositions described in Table 1 3) was prepared, and its physical property values were measured. The results were as follows.

The liquid crystal composition LC-1, LC-2 and LC-3 of the present invention, the viscosity (eta) is small, the rotational viscosity (.gamma.1) is small, since a large elastic constant _{(K 33), γ1 / K} 33 5 5.9, 5.7 and 5.5, which were significantly smaller than those of the comparative examples LC-A and LC-B. When the response speed of the liquid crystal display element using these was measured, LC-1, LC-2, and LC-3 were 3.3 to 3.5 msec, which was a sufficiently high speed response, whereas LC-A Was 4.2 msec, and LC-B was 4.1 msec. Furthermore, the voltage holding ratio (VHR) was measured and confirmed to have a high VHR. The cell thickness is 3.5 μm, the alignment film is JALS2096, the response speed measurement conditions are Von 5.5 V, Voff 1.0 V, measurement temperature 20 ° C., and AUTRONIC-MELCHERS DMS301 is used. It was. VHR measurement conditions were a voltage of 5 V, a frequency of 60 Hz, and a temperature of 60 ° C., and VHR-1 manufactured by Toyo Corporation was used.

Further, even when the conditions for injecting the liquid crystal cell (pressure and ODF method) were changed, no change was observed in the physical properties.
(Comparative Example 3 and Example 4)
LC-C (Comparative Example 3) and LC-4 (Example 4) having the compositions shown in Table 2 were prepared and measured for physical properties, which were as follows.

LC-4 is a liquid crystal composition of the present invention, the viscosity (eta) is small, the rotational viscosity (.gamma.1) is small, since a large elastic constant _{(K 33), γ1 / K} 33 is 5.8, compared The value was significantly smaller than that of LC-C3 as an example. When the response speed of the liquid crystal display element using these was measured, Example 4 had a sufficiently high response of 3.5 msec, while Comparative Example 3 had a response of 4.3 msec. Furthermore, the voltage holding ratio (VHR) was measured and confirmed to have a high VHR. The cell thickness is 3.5 μm, the alignment film is JALS2096, the response speed measurement conditions are Von 5.5 V, Voff 1.0 V, measurement temperature 20 ° C., and AUTRONIC-MELCHERS DMS301 is used. It was. VHR measurement conditions were a voltage of 5 V, a frequency of 60 Hz, and a temperature of 60 ° C., and VHR-1 manufactured by Toyo Corporation was used.

Further, even when the conditions for injecting the liquid crystal cell (pressure and ODF method) were changed, no change was observed in the physical properties.
(Comparative Example 4, Example 5, Example 6, Example 7 and Example 8)
LC-D (Comparative Example 4), LC-5 (Example 5), LC-6 (Example 6), LC-7 (Example 7) and LC-8 (Examples) having the compositions described in Table 2 8) was prepared, and the physical properties thereof were measured.

LC-5, LC-6, LC-7 and LC-8, which are liquid crystal compositions of the present invention, have a low viscosity (η), a low rotational viscosity (γ1), and a large elastic constant (K ₃₃ ). .gamma.1 / K ₃₃ was significantly smaller than that of the LC-D are comparative examples.
From the above, the liquid crystal composition of the present invention without reducing the Δn and T _ni, eta is sufficiently small, the rotational viscosity γ1 is sufficiently small, a large elastic constant K _33, the absolute value is large negative dielectric It was confirmed that the VA liquid crystal display element using this has an excellent anisotropy and a fast response speed.

Claims (15)

As the first component, the general formula (I)

Wherein R ¹¹ and R ¹² are each independently an 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 an alkenyloxyl group having 2 to 8 carbon atoms. X ¹¹ , X ¹² , X ¹³ , X ¹⁴ , X ¹⁵ , X ¹⁶ , X ¹⁷ and X ¹⁸ each independently represent a hydrogen atom, a fluorine atom or a chlorine atom. 2 or more species, the content is 3% to 45% by mass, and as the second component, general formulas (II-A) and (II-B)

Wherein R ¹ and R ² are each independently an 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 an alkenyloxyl group having 2 to 8 carbon atoms. the stands, ^{R 1} and ^{R 2} in present in one -CH ₂ - or nonadjacent two or more -CH ₂ - are each independently -O- and / or -S- to be substituted In addition, one or two or more hydrogen atoms present in R ¹ and R ² may be each independently substituted with a fluorine atom or a chlorine atom, and ring A and ring B are each independently Trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 3,5-difluoro-1,4- Phenylene group, 2,3-difluoro-1,4- Phenylene group, 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2 , 6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and p and q each independently represents 0, 1 or 2.) A liquid crystal composition containing one or more selected compounds . The dielectric anisotropy (Δε) at 25 ° C. is in the range of −2.0 to −8.0, the refractive index anisotropy (Δn) at 20 ° C. is in the range of 0.08 to 0.14, The viscosity (η) at 20 ° C. is in the range of 10 to 30 mPa · s, the rotational viscosity γ1 at 20 ° C. is in the range of 60 to 130 mPa · s, and the nematic phase-isotropic liquid phase transition temperature (T _ni ) is The liquid crystal composition according to claim 1, wherein the liquid crystal composition is in the range of 60 ° C. to 120 ° C. The liquid crystal composition according to claim 1 or 2, wherein the content of the second component is 10 to 90% by mass. General formulas (II-A) and (II-B) are general formulas (II-A1), (II-A2) and (II-B1).

(In the formula, R ³ and R ⁴ each independently represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, and one or more of R ³ and R ⁴ present in R ³ and R ⁴ The liquid crystal composition according to claim 1, wherein each hydrogen atom may be independently substituted with a fluorine atom. As the third component, from general formulas (III-A) to (III-J)

(Wherein R ⁵ is an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, R ⁶ is an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, and 2 to carbon atoms. 5 represents an alkenyl group of 5 or an alkenyloxyl group of 2 to 5 carbon atoms.) The compound according to any one of claims 1 to 4 , comprising one or more compounds selected from the group of compounds represented by: Liquid crystal composition. Formula (I), formula (II-A1) and a liquid crystal composition according to any one of the general formulas (II-A2) from claim 1 containing a compound represented by simultaneously 5. Formula (I), the general formula (II-A1), the general formula (II-A2) and the general formula (III-A) from claim 1 containing a compound represented by simultaneously according to any one of 5 Liquid crystal composition. Formula (I), formula (II-A1), the general formula (II-A2), the general formula (II-B1) and 5 claims 1 to general formula (III-A) represented by the compound containing simultaneously The liquid crystal composition according to any one of the above. General formula (V)

(Wherein R ²¹ and R ²² are each independently an 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 an alkenyloxy group having 2 to 8 carbon atoms) The liquid crystal composition according to any one of claims 1 to 8 , comprising one or more compounds represented by the formula: The liquid crystal according to claim 9, comprising simultaneously the compounds represented by formula (I), general formula (II-A1), general formula (II-A2), general formula (V) and general formula (III-A). Composition. The liquid crystal composition according to any one of claims 1 to 10 containing a polymerizable compound. As the polymerizable compound, the general formula (IV)

(Wherein R ⁷ and R ⁸ are each independently the following formulas (R-1) to (R-15):

X ¹ to X ⁸ each independently represents a trifluoromethyl group, a trifluoromethoxy group, a fluorine atom or a hydrogen atom. The liquid crystal composition according to claim 11 , comprising one or more polymerizable monomers represented by formula (1). The liquid crystal display element using the liquid-crystal composition of any one of Claim 1 to 12 . Active matrix driving liquid crystal display device using the liquid crystal composition according to any one of claims 1 to 12. VA mode using the liquid crystal composition according to any one of claims 1 to 12, PSA mode, PSVA mode, IPS mode or ECB mode liquid crystal display device.