JP6489382B2 - Nematic liquid crystal composition - Google Patents

Description

  The present invention relates to a nematic composition having a negative dielectric anisotropy useful as an electro-optical liquid crystal display material, and a liquid crystal display device using the same.

  Because of its excellent display quality, active matrix liquid crystal display devices are put on the market for portable terminals, liquid crystal televisions, projectors, computers and the like. In the active matrix display method, TFT (thin film transistor) or MIM (metal insulator metal) is used for each pixel, and high voltage holding ratio is regarded as important for this method. In order to obtain a wider viewing angle characteristic, a TFT display combined with VA, IPS, and OCB modes and a reflection type in ECB mode have been proposed to obtain a brighter display. In order to cope with such a display element, a new liquid crystal compound or liquid crystal composition is still proposed (see Patent Documents 1 and 2).

  In recent years, liquid crystal televisions employing the VA mode have begun to spread in earnest, and a number of liquid crystal compounds having negative dielectric anisotropy and liquid crystal compositions using the same have been disclosed. However, since the response speed when configured as a display element is particularly emphasized when used in a liquid crystal television, the conventional liquid crystal composition cannot sufficiently meet the requirements. For example, a liquid crystal composition using a bicyclohexane compound (see Patent Documents 3 and 4) has a certain effect on reducing the viscosity of a liquid crystal composition that is largely involved in response speed. However, when the response speed is emphasized and the content of the bicyclohexane compound is increased, the stability of the liquid crystal composition at a low temperature is impaired, and the viscosity has not yet satisfied the market demand.

  On the other hand, when a liquid crystal composition using a bicyclohexane compound in which an alkenyl group is introduced into the side chain is used in order to improve the response speed, there is a problem that the light resistance is not sufficient.

  To improve these issues,

  As a liquid crystal composition with improved light resistance of a liquid crystal material having a negative dielectric anisotropy, a bicyclohexane compound having an alkenyl group introduced into the side chain, a liquid crystal compound having a naphthalene skeleton, a liquid crystal compound having a chroman skeleton, and ultraviolet absorption Although a specific example (see Patent Document 5) in combination with an agent is disclosed, it may be actively developed because it may induce various display defects derived from ultraviolet absorbers in exchange for improvement in light resistance. It has not been done.

  In other words, liquid crystal compositions having a negative dielectric anisotropy have not yet improved response speed, light resistance and low-temperature stability, and the liquid crystal compositions having a negative dielectric anisotropy have been solved simultaneously. It was difficult to get things.

JP-A-2-233626 Special Publication 4-501575 Publication JP 59-70624 JP 60-16940 JP 2006-124544 A

  The problem to be solved by the present invention is to provide a liquid crystal composition having a high-speed response, light resistance and low-temperature stability suitable for liquid crystal television applications and having a negative dielectric anisotropy, and using the same The object is to provide a liquid crystal display element.

  The present invention, as a result of intensive studies to solve the above problems, the formula (1) as the first component

And a compound having a negative dielectric anisotropy Δε and an absolute value larger than 3 as a second component, and a nematic phase-isotropic liquid phase transition temperature of 60 ° C. to 120 ° C. ° C, solid phase or smectic phase-nematic phase transition temperature is -80 ° C to -20 ° C, refractive index anisotropy Δn is 0.05 to 0.15, and dielectric anisotropy Δε is -1.5 to -8.0. The present invention relates to a nematic liquid crystal composition and a liquid crystal display device using the same.

  By combining the liquid crystal compounds of the present invention, a liquid crystal composition for an active matrix type liquid crystal display device having high-speed response, excellent light resistance and low-temperature stability while satisfying various characteristics required for a liquid crystal television was obtained. This provides a liquid crystal display element having a long lifetime due to high reliability while maintaining or improving display quality, and is particularly useful as an active matrix liquid crystal display element for a liquid crystal television in a transmission mode. .

  The liquid crystal composition of the present invention contains the compound represented by the formula (1), but preferably 5 to 25%.

  Further, the second component contains a compound having a negative dielectric anisotropy Δε and an absolute value larger than 3, but the second component is represented by the general formula (2) or (3)

(Wherein R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 15 carbon atoms, and B ^{1 to} B ⁴ each independently represents a trans-1,4-cyclohexylene group or 1,4- Represents a phenylene group, and L ^{1 to} L ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —COO—, —OCH ₂ —, —CH ₂ O—, —OCF ₂ -or CF ₂ O-, m, n, o and p each independently represent 0, 1 or 2, m + n and o + p each independently represent 0, 1, 2 or 3 X ^{1 to} X ⁵ each independently represents H, F or Cl. When the compound represented by the general formula (2) or (3) is contained, it is preferably contained in two or more kinds, more preferably 3 to 15 kinds are represented by the general formula (2) or (3). 5 to 75%, more preferably 10 to 60%, and particularly preferably 10 to 40%.

  The liquid crystal composition of the present invention may contain 5 to 25% of the compound represented by the formula (1) and 5 to 75% of the compound represented by the general formula (2) or the general formula (3). preferable.

  Further, the liquid crystal composition of the present invention more preferably contains the formula (1), the general formulas (2) and (3) at the same time.

In the general formulas (2) and (3), R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 15 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.

B ^{1 to} B ⁴ each independently represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group which may be fluorine-substituted, but the trans-1,4-cyclohexylene group is more preferable.

L ^{1 to} L ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —COO—, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, or CF. ₂ O— represents a single bond, —CH ₂ CH ₂ —, —OCH ₂ —, —CH ₂ O— is more preferable.

  m + n and o + p each independently represents 0, 1, 2 or 3, with 1 or 2 being more preferred.

  More specifically, the compound represented by the general formula (2) is more preferably a compound represented by the general formula (2-1) or (2-2).

  More specifically, the compound represented by the general formula (3) is more preferably a compound represented by the general formula (3-1).

  In order to adjust the physical properties of the liquid crystal composition of the present invention, the general formula (4) or (5)

(Wherein R ^{5 to} R ⁸ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, and ring A to ring E each independently represent a trans-1,4-cyclohexylene group or 1,4-phenylene group, H atoms in these groups may be each independently substituted with CH ₃ , F or Cl, L ^{5 to} L ⁸ are each independently a single bond,- _{, - - CH 2 CH 2 (} CH 2) 4 -, - OCH 2 -, - CH 2 O -, - OCF 2 - or CF ₂ O-to represent, q and r represent each independently 0-2 , X ^{6 to} X ⁷ each independently represents H, F, or Cl.) 1 or 2 or more compounds may be contained. However, in the general formula (4), the compound represented by the formula (1) is excluded.

  When the compound represented by the general formula (4) or (5) is contained in one kind or two or more kinds, it is preferably contained in two or more kinds, and more preferably in two to ten kinds.

  The content of the compound represented by the general formula (4) or (5) is preferably 5 to 80%, more preferably 10 to 60%, and particularly preferably 20 to 50%. .

R ^{5 to} R ⁸ each independently represents an alkyl group or an alkoxyl group having 1 to 10 carbon atoms, and an alkyl group or an alkoxyl group having 1 to 5 carbon atoms is more preferable.

L ^{5 to} L ⁸ each independently represents a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, or CF ₂ O—. Are more preferably a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—.

X ^{6 to} X ⁷ each independently represent H, F, or Cl, more preferably —H or F, and particularly preferably X ¹ = X ² = F.

  More specifically, the compound represented by the general formula (4) is more preferably a compound represented by the general formulas (4-1) to (4-7).

  The compound represented by the general formula (5) is more preferably a compound represented by the general formulas (5-1) to (5-6).

-In addition to the above-mentioned compounds, normal nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, or the like may be contained.

In the liquid crystal composition of the present invention, the nematic phase-isotropic liquid phase transition temperature (T _NI ) is 60 to 120 ° C, more preferably 70 to 105 ° C, and particularly preferably 75 to 95 ° C. The solid phase or smectic phase-nematic phase transition temperature (T _{→ N} ) is -80 to -20 ° C, more preferably -20 ° C or less, and particularly preferably -30 ° C or less. The refractive index anisotropy (Δn) at 25 ° C. is 0.05 to 0.15, more preferably 0.07 to 0.13, and particularly preferably 0.08 to 0.11. The dielectric anisotropy (Δε) at 25 ° C. is −1.5 to −8.0, more preferably −1.5 to −5.0, and particularly preferably −1.5 to −3.5.

  The liquid crystal composition of the present invention is useful for a liquid crystal display element, but is particularly useful for a liquid crystal display element for driving an active matrix, and can be used for a liquid crystal display element for a transmission mode, a reflection mode, or a transflective mode.

  Hereinafter, although an example is given and the present invention is explained still in full detail, the present invention is not limited by these. “%” Means “% by mass”.

T _NI : Nematic phase-isotropic liquid phase transition temperature (℃) is the upper limit temperature of liquid crystal phase
T _{→ N} : The solid phase or smectic phase-nematic phase transition temperature (° C.) is set as the liquid crystal phase lower limit temperature.

Δε: dielectric anisotropy at 25 ° C. Δn: refractive index anisotropy at 25 ° C. η: viscosity at 20 ° C.
VHR (UV): Voltage holding ratio at 25 ° C after UV irradiation (%)
(Note that the measurement conditions of the voltage holding ratio are applied voltage 5V, frame time 16.5ms, pulse width 64μsec. The UV irradiation lamp uses FL15BL-360 manufactured by Mitsubishi Electric OSRAM Co., Ltd., and VA mode in which liquid crystal is injected. The cell (cell thickness 3.5um, alignment film RN-1517) was irradiated with ultraviolet rays for 60 minutes.)

  The following abbreviations are used in the description of compounds.

n- C _n H _{2n + 1-}
-2- -CH ₂ CH ₂ -
-1O- -CH ₂ O-
-O1- -OCH _2-
-On -OC _n H _{2n + 1}
ndm- C _n H _{2n + 1} -C = C- (CH ₂ ) _m-1-

  Table 1 shows the compositions and physical properties of Example 1 (No. 1), Comparative Example 1 (R1), and Comparative Example 2 (R2), which are liquid crystal compositions of the present invention.

Example 1 (No. 1) satisfied the physical property values required for a liquid crystal television, and the VHR (UV) value was good. On the other hand, the liquid crystal composition of Comparative Example 1 (R1) is Comparative Example 3 described in Patent Document 5, does not include the compounds represented by Formula (1) and General Formula (3), and has a VHR (UV) value of It was low. Comparative Example 2 (R2) is a liquid crystal composition that uses a lot of low-viscosity bicyclohexane compounds to improve response speed, but T _{→ N} is too high at -5 ° C and is practical from the viewpoint of low-temperature stability. Not right. From the above, Example 1 (No. 1), which is a liquid crystal composition of the present invention, satisfies various properties required for a liquid crystal television, has excellent light resistance, has good low-temperature stability, and has a long lifetime. It can be seen that the present invention is very useful as an active matrix type liquid crystal display element.

  Further, Table 2 shows the composition and physical property values of Example 2 (No. 2) and Comparative Example 3 (R3).

  Example 2 (No. 2) satisfied various characteristics like Example 1, and was confirmed to be very useful. On the other hand, the liquid crystal composition of Comparative Example 3 (R3) is Comparative Example 4 described in Patent Document 5, which does not satisfy the conditions of the present invention and shows that VHR (UV) is low.

  Further, Table 3 shows the compositions and physical property values of Example 3 (No. 3), Example 4 (No. 4), and Example 5 (No. 5).

  Example 3 (No. 3), Example 4 (No. 4), and Example 5 (No. 5) satisfied the preferable conditions of the present invention and were confirmed to be very useful.

Claims (10)

Formula (1) as the first component

And a compound having a negative dielectric anisotropy Δε and an absolute value larger than 3 as the second component,
General formula (5)

(Wherein R ^{7 to} R ⁸ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, and ring D to ring E each independently represent a trans-1,4-cyclohexylene group or 1 , 4-phenylene group represents, ^{L 7} represents a single bond, ^{L 8} represents a single bond, r is represents 0 to ^2, although X 6 to X ⁷ each independently represent H or F, below Excluding the compounds represented by the general formulas (4-3) and (4-5), containing one or more compounds represented by
Formula (4-1-1)

Containing a compound represented by
Formula (4-3) or (4-5)

(Wherein R ^{5 to} R ⁶ each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxyl group),
Does not contain compounds with alkenyl groups,
The nematic phase-isotropic liquid phase transition temperature is 60 ° C. to 120 ° C., the solid phase or smectic phase—nematic phase transition temperature is −80 ° C. to −20 ° C., and the refractive index anisotropy Δn is 0.05. A nematic liquid crystal composition having a dielectric anisotropy Δε of −1.5 to −8.0. General formula (4)

(Wherein R ^{5 to} R ⁶ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, and ring A to ring C each independently represent a trans-1,4-cyclohexylene group or 1,4-phenylene group, H atoms in these groups may be each independently substituted with CH ₃ , F or Cl, L ^{5 to} L ⁶ are each independently a single bond, CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ — or CF ₂ O— is represented, and q represents 0 to 2. However, Formula (1) ) , A compound represented by formula (5), formula (4-1-1), formula (4-3) and formula (4-5) . The nematic liquid crystal composition according to claim 1, which is contained. As the compound represented by the general formula (5), r represents 0 or 1, R ⁷ represents an alkyl group having 1 to 10 carbon atoms, R ⁸ is and characterized by containing a compound which an alkoxyl group The nematic liquid crystal composition according to claim 1 or 2. As a compound represented by the general formula (4), the general formulas (4-1) , (4-2), (4-4), (4-6) and (4-7)

(In formula, R < ⁵ > -R < ⁶ > represents a C1-C10 alkyl group or an alkoxyl group each independently. However, the compound represented by Formula (1) and (4-1-1) is remove | excluded. The nematic liquid crystal composition according to claim 2, wherein the nematic liquid crystal composition comprises one or more compounds selected from the group consisting of compounds represented by:   The nematic liquid crystal composition according to any one of claims 1 to 4, comprising 5 to 25% of a compound represented by the structural formula (1). The second component is represented by the general formula (2) or (3)

(Wherein R ^{1 to} R ⁴ each independently represents an alkyl group having 1 to 15 carbon atoms, and B ^{1 to} B ⁴ each independently represents a trans-1,4-cyclohexylene group or 1,4- Represents a phenylene group, and L ^{1 to} L ⁴ each independently represent a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —COO—, —OCH ₂ —, —CH ₂ O—, —OCF. ₂ -or CF ₂ O-, m, n, o and p each independently represent 0, 1 or 2, m + n and o + p each independently represent 0, ¹ , 2 or 3, X ¹ to X ⁵ each independently H, F or an Cl.) is a compound represented by the nematic liquid crystal composition according to any one of claims 1 to 5.   The nematic liquid crystal composition according to claim 6, comprising 5 to 25% of the compound represented by the formula (1) and 5 to 75% of the compound represented by the general formula (2) or the general formula (3).   A liquid crystal display element using the nematic liquid crystal composition according to claim 1.   A liquid crystal display element for driving an active matrix using the nematic liquid crystal composition according to claim 1.   A VA mode, IPS mode or ECB mode liquid crystal display element using the nematic liquid crystal composition according to claim 1.