JPH1046150A - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Abstract

(57) [Problem] To provide a nematic liquid crystal material having a small birefringence, a wide temperature range in which it can be driven, and excellent responsiveness, and an electric device using this composition as a constituent material. An object of the present invention is to provide a liquid crystal display device such as a TN-LCD, a STN-LCD, a TFT-LCD, etc., having improved optical characteristics. SOLUTION: General formula (I) (R ¹¹ , R ¹² : each independently a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms, p, q: each independently an integer of 0 to 4)
Liquid crystal component A containing at least one compound represented by the formula:
And a liquid crystal material containing a liquid crystal component B containing at least two compounds having a dielectric anisotropy of +2 or more, wherein the liquid crystal material has a dielectric anisotropy of 3 or more and a nematic phase of 60 ° C. or more. A nematic liquid crystal composition characterized by having an isotropic liquid phase transition temperature and a crystal phase of 0 ° C. or lower or a smectic phase-nematic phase transition temperature, and a liquid crystal display device using the same.

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 display material and a liquid crystal display using the same.

[0002]

2. Description of the Related Art A typical liquid crystal display element is a TN-LCD.
(Twisted nematic liquid crystal display element)
It is used in watches, calculators, electronic organizers, pocket computers, word processors, personal computers and the like. On the other hand, with the increase in processing information of OA equipment, Scheffer et al. [SID '85 Digest, p.120 1985
Year], Kinukawa et al. [SID '86 Digest, p.122 1986], STN (Super Twisted Nematic) -L
CDs have been developed and have begun to spread widely in displays for high information processing such as portable terminals, word processors, and personal computers.

Recently, an active addressing drive system [Proc. 12th IDRC p.5
03 1992] and multi-line addressing drive system [S
ID'92 Digest, p.232 1992] has been proposed. In addition, as a method for performing color display without using a color filter layer, a new reflective color liquid crystal display system using the birefringence of a liquid crystal and a retardation plate [Technical Report of the Institute of Television Engineers of Japan vol.14 No10.p.51 1990 Year] has been proposed. As such a liquid crystal material, a material having an elastic constant ratio K33 / K11 of about 1.5 and having a relatively small dielectric anisotropy Δ △ and a low viscosity is required. In particular, for the purpose of obtaining a wider viewing angle characteristic, a birefringence Δn having a relatively small or medium birefringence is required, and new liquid crystal compounds or liquid crystal compositions have been proposed at present.

Further, due to its excellent display quality, active matrix type liquid crystal display devices have been put on the market for portable terminals, liquid crystal televisions, projectors, computers and the like. In the active matrix display method, a TFT (thin film transistor) or a metal insulator metal (MIM) is used for each pixel, and a high voltage holding ratio is emphasized in this method. In addition, in order to obtain a wider viewing angle characteristic, a super TFT [Asia Display '95 Diges
t, p. 707 1995] by Kondo et al. (hereinafter, these active matrix display type liquid crystal display elements are collectively referred to as TFT-LCD). In order to cope with such a display element, proposals have been made at present, such as those described in new liquid crystal compounds or liquid crystal compositions, for example, Japanese Patent Application Laid-Open No. 6-312949 and Japanese Patent Publication No. 5-501735.

[0005]

In order to improve the liquid crystal display characteristics as described above, it is necessary to have a birefringence .DELTA.n in the range of 0.07 to 0.16 and obtain a high-speed response of the liquid crystal display. A lower viscosity liquid crystal material is needed. There is also a need for higher chemical stability of the liquid crystal material and wider characteristics of the driving temperature range. For this purpose, for example, the following general formulas (a-1) to (a-3)

[0006]

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(Wherein R and R ′ are alkyl groups and r is an integer), and the like have been used. However, problems still remain. Specifically, when the compounds of the general formulas (a-1) to (a-3) are frequently used to achieve the above-mentioned object, there is a specificity in compatibility and a tendency that a smectic phase or a crystal phase tends to appear. Had. Also,
Regarding the technology relating to the compound represented by the general formula (I) according to the present invention, knowledge of its physical properties and mixtures has not yet been reported.

SUMMARY OF THE INVENTION An object of the present invention is to solve or improve the above-mentioned problems. A nematic liquid crystal composition having a small birefringence Δn, a wide temperature range in which it can be driven, and excellent responsiveness is provided. It is an object of the present invention to provide a liquid crystal display device such as a TN-LCD, an STN-LCD, a TFT-LCD, etc. using the liquid crystal composition as a constituent material and having improved electro-optical characteristics.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present invention, etc. General formula (I)

[0010]

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(Wherein R ¹¹ and R ¹² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms;
p and q each independently represent an integer of 0-4. Liquid crystal components A and + containing at least one compound represented by formula (I):
A liquid crystal material containing a liquid crystal component B containing at least two compounds having two or more dielectric anisotropies, wherein the liquid crystal material has a dielectric anisotropy of 3 or more and a nematic phase of 60 ° C. or more. A nematic liquid crystal composition having an isotropic liquid phase transition temperature and a crystal phase of 0 ° C. or lower or a smectic phase-nematic phase transition temperature. 2. (1) wherein the liquid crystal component A contains at least one compound of the general formula (I) in which R ¹¹ and / or R ¹² is a hydrogen atom.
The nematic liquid crystal composition according to the above. 3. (1) The liquid crystal component (A), wherein in the general formula (I), n is an integer of 0, 2, or 4, and at least one kind of compound is contained.
Or the nematic liquid crystal composition according to 2. 4. The liquid crystal material contains 1 to 40% by weight of the liquid crystal component A.
4. The nematic liquid crystal composition according to the above item 1, 2 or 3, which is contained. 5. The liquid crystal component B has a general formula (II-1) to (II-3)

[0012]

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(Wherein, R ^{21 to} R ²³ each independently represent a linear alkyl group, alkenyl group or C _s group having 2 to 7 carbon atoms)
Represents _{H 2s + 1 -O-C t} H 2t, s and t are each independently 1
X ^{21 to} X ²³ each independently represent F or C
1, represents —OCF ₃ , —OCHF ₂ , —CF ₃ or —CN;
²¹ to Y ²⁹ each independently represent a hydrogen atom or a fluorine atom, Z ^{2 1} ~Z ²³ each independently represents a single bond, -COO -, - C ₂
H ₄ — or —C ₄ H ₈ —, and Z ²¹ also represents —C≡C— or —C
H may be CH =, Z ²⁴ and Z ²⁵ each independently represent a single bond, —COO— or —C≡C—, l and m each independently represent 0 or 1, The hydrogen atom (H) of the cyclohexane ring in the compound may be replaced by a deuterium atom (D). 5. The nematic liquid crystal composition according to the above 1, 2, 3 or 4, comprising at least two compounds selected from the group of compounds represented by the formula (1). 6. The liquid crystal component B comprises at least one compound represented by formulas (II-1) to (II-3) wherein R ^{21 to} R ²³ each independently represent an alkenyl group having 2 to 7 carbon atoms. 6. The nematic liquid crystal composition according to the above item 5, which contains: 7. In the general formulas (II-1) to (II-3), X ^{21 to} X ²³ each independently represent F, Cl, —OCF ₃ ,
Or the nematic liquid crystal composition according to the above item 5 or 6, comprising at least one compound represented by -CN. 8. Wherein the liquid crystal material contains 10 to 99% by weight of the liquid crystal component B.
8. The nematic liquid crystal composition according to 6 or 7. 9. 9. The nematic liquid crystal composition according to the above 5, 6, 7 or 8, wherein the liquid crystal component B contains 1 to 100% by weight of the compounds of the general formulas (II-1) to (II-3). 10. The liquid crystal material contains a liquid crystal component C, and the liquid crystal component C has a general formula (III-1) to (III-3)

[0014]

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(In the formula, R ^{31 to} R ³³ each independently represent a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^{34 to} R ³⁶ each independently represent 1 to 7 carbon atoms. 7 linear alkyl group, an alkoxy group, an alkenyl group, alkenyloxy group or _{C u H 2u + 1 -O-} C v t H 2v, u and v are each independently an integer of 1 to 5 , Y ³¹ to Y ³⁴ each independently represents H, F or CH _3, Z ³¹ ~Z ³⁴ each independently represents a single _{bond, -COO -, - C 2 H} 4 - or -C ₄ H ₈ - And Z ³¹ may also be —C≡C— or —CH ＝ CH—; Z ³⁵ represents a single bond, —C≡C— or —COO—;
³¹ and ring A ³² each independently represent a cyclohexane ring or a cyclohexene ring, i, j and k each independently represent 0 or 1
And the hydrogen atom (H) of the cyclohexane ring in each compound may be substituted with a deuterium atom (D). 1, 2, 3, 4, 5, 6, 7,
10. The nematic liquid crystal composition according to 8 or 9. 11. The liquid crystal material contains at most 75
11. The nematic liquid crystal composition according to the above item 10, wherein the composition is contained by weight. 12. The liquid crystal material has a dielectric anisotropy of 4 to 25, a nematic phase-isotropic liquid phase transition temperature of 70 ° C. or more, and a crystal phase or a smectic phase-nematic phase transition temperature of −10 ° C. or less. 12. The nematic liquid crystal composition according to any one of the above items 1 to 11, wherein 13. The birefringence of the liquid crystal material is 0.07 to 0.16
13. The nematic liquid crystal composition according to any one of the above items 1 to 12, wherein 14． 14. An active matrix liquid crystal display device using the nematic liquid crystal composition according to any one of the above 1 to 13. 15. A twisted nematic or super twisted nematic liquid crystal display using the nematic liquid crystal composition described in 1 to 13 above. Was found as a means for solving the above-mentioned problem.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of the nematic liquid crystal composition of the present invention and a liquid crystal display using the same will be described.

The compound represented by the general formula (I) has a low viscosity, a small birefringence Δn, a large elastic constant ratio, excellent high-speed response, and a mixture with other liquid crystal materials. Nematic phase-isotropic liquid phase transition temperature T
_NI has been improved to a relatively high temperature, has excellent compatibility, can have a wider display temperature range, has a dielectric anisotropy in the range of -2 to +2, and has higher chemical stability. doing. From such a viewpoint, a more preferable form of the compound represented by the general formula (I) is a compound in which R ¹¹ and R ¹² are each represented by a hydrogen atom and / or a compound in which n is 0, 2 or 4. A nematic liquid crystal composition containing at least one selected material is preferred.

More specifically, a compound selected from the group of compounds represented by formulas (I-1) to (I-3) is used. In addition, each compound was used after removing impurities by a method such as distillation, column purification, recrystallization, etc. and sufficiently purified.

[0019]

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The liquid crystal composition of the present invention containing the liquid crystal component A containing at least one kind of the compound represented by the general formula (I) includes TN-LCD, STN-LCD,
A liquid crystal display device such as an FT-LCD is made to have more improved electro-optical characteristics, and in particular, the response at a low temperature and the temperature dependency of a steep driving voltage are made more preferable.

One or more compounds of the general formula (I) can be contained as the liquid crystal component A, but the effects described above can be obtained even with one compound. The liquid crystal component A can be contained in the range of 1 to 40% by weight, more preferably 5 to 30% by weight, based on the liquid crystal composition of the present invention.

The liquid crystal composition of the present invention contains, in addition to the above liquid crystal component A, a liquid crystal component B containing at least two compounds having a dielectric anisotropy of +2 or more. The liquid crystal compound having a dielectric anisotropy larger than 2 described in the present invention has the following significance. The chemical structure of the liquid crystal compound is rod-shaped, and has a core structure in which the central portion has one to four six-membered rings. A terminal group substituted at a position corresponding to the direction, and at least one of the terminal groups present at both ends is a polar group, that is, for example, -CN, -OCN, -N
_{CS, -F, -Cl, -NO 2} , -CF 3, -OCF 3, -OCHF
₂ is a compound. As a result, the optical anisotropy of the liquid crystal layer can be set to a predetermined value, can be electrically driven, and the operating temperature range can be widened.

The compound having a dielectric anisotropy of +2 or more requires at least two or more compounds, and preferably has a range of 3 to 15 types. A compound having a dielectric anisotropy of +8 to +13, +1
It is preferable to appropriately select from the compounds of 4 to +18 and the compounds of +18 or more, and a predetermined driving voltage and response characteristics can be obtained. In this case, it is preferable to mix at most 10 or less compounds with dielectric anisotropy of +8 to +13, and it is preferable to mix at most 8 compounds with +14 to +18. It is preferable to mix at most 10 or less of the above compounds. Use of the liquid crystal component B as described above gives a more favorable effect to the temperature characteristics of the display characteristics. More specifically, drive voltage, contrast related to steepness,
Temperature dependency such as responsiveness is more preferable. The liquid crystal component B can be contained in the range of 10 to 99% by weight, and more preferably in the range of 25 to 70% by weight.

The crystal phase or smectic phase-nematic phase transition temperature T → _N is 0 ° C. or lower, preferably −10 ° C. or lower, more preferably −20 ° C. or lower, and particularly preferably −3 ° C. or lower.
0 ° C. or less. The nematic phase-isotropic liquid phase transition temperature T _NI is 60 ° C. or higher, preferably 70 ° C. or higher, and more preferably 80 ° C. to 130 ° C. The liquid crystal composition of the present invention requires a dielectric anisotropy of 3 or more and 4 to 40.
Is preferable, and when high-speed response is important, 4-1
17 if the range of 6 requires a lower drive voltage
The range of ~ 25 is preferred. Further, the birefringence Δn is set at 0.
06 or more is required, and the range of 0.07 to 0.16 is particularly preferable. Such properties of the nematic liquid crystal composition are useful for use in an active matrix type, twisted nematic or super twisted nematic liquid crystal display device.

The above nematic liquid crystal composition is useful for TN-LCDs and STN-LCDs having a high response speed, and can provide color display by the birefringence between the liquid crystal layer and the retardation plate without using a color filter layer. The present invention is useful for a liquid crystal display device which can be used, and a transmissive or reflective liquid crystal display device can be used. This liquid crystal display element has a substrate having a transparent electrode layer and at least one of which is transparent, and the molecules of the nematic liquid crystal composition are twisted between the substrates. °, preferably from 90 ° to 270 °, preferably from 45 ° to 135 ° or from 180 ° to 26 °.
It is particularly preferred to select in the range of 0 °. in this case,
The pretilt angle obtained by the alignment film provided on the transparent electrode substrate is preferably selected in the range of 1 ° to 20 °, and the twist angle is preferably 30 ° to 100 °, and the pretilt angle of 1 ° to 4 ° is preferable. 2 ° from 100 ° to 180 °
A pretilt angle of ６6 ° is preferred, and 180 ° -260 °
In this case, a pretilt angle of 3 ° to 12 ° is preferable, and 260 °
At ~ 360 °, a pretilt angle of 6-20 ° is preferred.

The liquid crystal component B described above has the general formula (II-
1) Two or more compounds selected from the second compound group represented by (II-3) can be used, and the second compound group can be contained in the range of 1 to 100% by weight, 50
The range is preferably from 100 to 100% by weight. General formula (II-1)
A more preferred form of the compound represented by (II-3) is a compound wherein R ^{21 to} R ²³ are an alkenyl group having 2 to 7 carbon atoms and / or X ^{21 to} X ²³ are F, Cl, —OC.
A nematic liquid crystal composition containing at least one compound selected from compounds represented by F ₃ or —CN is preferable. More specifically, they are compounds represented by formulas (II-4) to (II-21). The dielectric anisotropy of these compounds is +2 or more. In addition, each compound was used after removing impurities by a method such as distillation, column purification, recrystallization, etc. and sufficiently purified.

[0027]

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[0028]

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[0029]

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The liquid crystal composition of the present invention has the general formula (II-1)
By containing a compound selected from the second compound group of (II-3), the driving voltage can be reduced, the viscosity is relatively small, and the specific resistance and the voltage holding ratio are relatively high. . In particular, the compounds of the general formulas (II-4) to (II-10) and the general formulas (II-12) to (II-16) are excellent in this effect. In addition, general formulas (II-13), (II-15), (II-17)
The compound (II-21) is excellent in that this effect can be obtained by adding a small amount of 0.5 to 30%.

More specifically, R^{twenty one}Has 2 to 2 carbon atoms
5 alkyl groups or alkenyl groups are preferred.
At least one compound having a kenyl group is contained
Preferably. R^{twenty two}Is alkyl having 2 to 5 carbon atoms
, Alkenyl or alkoxy compounds are preferred
No. X^{twenty one}~ X^{twenty three}Is F, Cl, -OCF_Three, -CN is a compound
It is preferable to use a lot of objects, and high-speed response is important
X^{twenty one}~ X^{twenty three}Is F, -OCF_ThreeUse a lot of compounds
Is preferable, and when a larger birefringence is required, X
^{twenty one}~ X^{twenty three}Is Cl, -OCF_Three, -CN
If a lower drive voltage is required,
X^{twenty one}~ X^{twenty three}Frequently use compounds in which is Cl or -CN
Is preferred. Also, active matrix display method,
Super combined with TFT-LCD, MIM-LCD, IPS mode
-The TFT display device has X^{twenty one}~ X^{twenty three}Is -F
Is preferably used. Y^{twenty one}~ Y²⁹Is fast response
It is preferable to use a lot of compounds in which H is important when
To improve the temperature dependence of the drive voltage^{twenty one}~ Y
²⁹Is F, particularly preferably Y^{twenty one}, Y^{twenty three}, Y^{twenty five}~
²⁷, Y²⁹It is preferable to frequently use a compound wherein F is
Y^{twenty five}, Y²⁶If F is Y^{twenty four}Is a compound wherein is H
Can further improve compatibility, and in the case of general formula (II-3)
Is Y²⁹Is more compatible by selecting a compound where is F
Can be improved. Z^{twenty one}~ Z^{twenty three}Is a single bond, -COO-, -C_TwoH
_Four-, -C_FourH₈-Can be Z^{twenty one}And Z^{twenty two}One of them is simply
Compounds with a bond are preferred to improve responsiveness and compatibility at low temperatures.
To improve, a single bond compound and -C_TwoH_Four-Combination of compounds
It is preferable to use them. Z _{twenty four}, Z_{twenty five}Is a single bond, -C
OO-, -C≡C-, and more emphasis on responsiveness
In this case, it is preferable to use a single bond compound frequently.
l and m represent 0 or 1, and are represented by the general formulas (II-1) and (II-2)
In which l and m are 0, and compounds represented by general formulas (II-1) and (II
-2) a compound wherein l and m are 1 and a compound of the general formula (II-3)
The mixing ratio with the compound is in the range of 0 to 100 to 100 to 0.
Timely choice, higher T_NIWhere you need
Where l and m in the general formulas (II-1) and (II-2) are 1
It is preferable to use the compound and the compound of the general formula (II-3) frequently.
New In the cyclohexane ring of formulas (II-1) and (II-2)
In which the hydrogen atom (H) is replaced by a deuterium atom (D)
Can be used, but this compound is used in the liquid crystal composition.
Adjustment of elastic constant and adjustment of pretilt angle corresponding to alignment film
Substituted with a deuterium atom (D)
It is preferable to include at least one compound.
No.

The present invention further provides, in addition to the above nematic liquid crystal composition, a liquid crystal compound of the liquid crystal component C represented by the general formula (III-
Compounds selected from the third compound group represented by 1) to (III-3) can be contained. By containing a compound selected from the compound group of the general formulas (III-1) to (III-3) as the liquid crystal component C, the viscosity can be reduced and the specific resistance and the voltage holding ratio are relatively high. Having. In particular, compounds represented by the following formulas (III-4) to (III-19) are preferable, and a preferable effect can be obtained by including at least one compound in which R ^{31 to} R ³³ are alkenyl groups. The compounds of the general formulas (III-4) to (III-19) are preferably used in an amount of 30% by weight or less.
Is preferably used in a total amount of 75% by weight or less.

[0033]

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[0034]

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The liquid crystal composition of the present invention has the above general formula (I-
In addition to the compounds represented by 1) to (III-3), in order to improve the properties of the liquid crystal composition, the liquid crystal composition contains a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, and the like, which are recognized as liquid crystal compounds. Is also good. However, if these compounds are used in a large amount, the properties of the nematic liquid crystal composition will be reduced. Therefore, the amount added is limited according to the required properties of the obtained nematic liquid crystal composition.

[0036]

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 means “% by weight”.

The chemical stability of the composition was as follows: liquid crystal composition 2 g
Was placed in an ampoule tube, vacuum-degassed, and then subjected to a process of purging with nitrogen and sealed. A heating promotion test at 150 ° C. for 1 hour was performed to measure a voltage holding ratio of the liquid crystal composition. 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.) V _th : When a TN-LCD having a cell thickness of 6 μm is formed. Γ: ratio of saturation voltage (V _sat ) to V _th Δε: dielectric anisotropy Δn: birefringence η: viscosity at 20 ° C. (cp)

(Example 1)

[0040]

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Nematic liquid crystal composition No. 3-
No. 1 was prepared and the properties of this composition were measured. The results were as follows. T _NI : 102.0 ° C. T → _N : -12. ° C. V _th : 2.46 V Δε: 3.0 Δn: 0.079 η: 12.9 c. p.

(Comparative Example 1)

[0043]

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A comparative liquid crystal composition (a-4) was prepared, and various characteristics of the composition were measured. The results were as follows. T _NI : 101.1 ° C. T → _N : 0. ° C _Vth : 2.44 V Δε: 3.0 Δn: 0.078 η: 13.7 c. p.

The difference from Example 1 is that the compound represented by the general formula (I) is changed to a compound represented by the general formula (a-1). Comparing the characteristics, the liquid crystal composition of the present invention showed that the viscosity was more preferable despite the fact that the temperature range of the nematic phase was wider and the number of carbon atoms was large.

(Comparative Example 2)

[0047]

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A comparative liquid crystal composition (a-5) was prepared, and various characteristics of the composition were measured. The results were as follows. _{T NI: 104.0 ℃ T → N} : 11. ° C _Vth : 2.41 V Δε: 3.0 Δn: 0.076 η: 17.3 c. p.

The difference from Example 1 is that the compound represented by the general formula (I) is changed to a compound represented by the general formula (a-2). Comparing the characteristics, the liquid crystal composition of the present invention showed that the temperature range of the nematic phase was wider and the viscosity was more preferable.

(Example 2)

[0051]

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The nematic liquid crystal composition No. 3-
2 was prepared, and various properties of the composition were measured. The results were as follows. T _NI : 101.0 ° C. T → _N : −30. ° C _Vth : 2.67 V Δε: 3.8 Δn: 0.077 η: 18.0 c. p. Voltage holding ratio before test: 99.6% Voltage holding ratio after heating acceleration test: 99.0%

Since the nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, it can be understood that the composition is thermally stable. Further, when an active matrix liquid crystal display device using this composition as a constituent material was produced, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.

(Embodiment 3)

[0055]

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The nematic liquid crystal composition No. 3-
No. 3 was prepared, and various properties of this composition were measured. The results were as follows. T _NI : 72.0 ° C. T → _N : −40. ° C _Vth : 1.97 V Δε: 5.6 Δn: 0.086 η: 14.3 c. p.

A chiral substance "S-811" (manufactured by Merck) was added to this nematic liquid crystal composition to prepare a mixed liquid crystal. On the other hand, "San Ever
An alignment film was formed by rubbing an organic film of "610" (manufactured by Nissan Chemical Industries, Ltd.) to produce an STN-LCD display cell having a twist angle of 220 degrees. The mixed liquid crystal was injected into this cell to construct a liquid crystal display, and the display characteristics were measured. As a result, a liquid crystal display device exhibiting STN-LCD display characteristics with excellent high time division characteristics and improved fast response was obtained. Also, 50 ° C to -20 ° C
The change of the drive voltage in the temperature range of was measured.
It was as small as 0 mV / ° C. and exhibited stable display characteristics over a wide temperature range. The chiral substance was added so that the intrinsic helical pitch P of the mixed liquid crystal and the cell thickness d of the display cell by the addition of the chiral substance were Δn · d = 0.85 and d / P = 0.53.

(Example 4)

[0059]

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The nematic liquid crystal composition No. 3-
No. 4 was prepared, and various properties of this composition were measured. The results were as follows. T _NI : 81.8 ° C. T → _N : −70. ° C _Vth : 2.27 V γ: 1.12 Δε: 7.1 Δn: 0.137 η: 17.8 c. p.

This nematic liquid crystal composition has a limit value of 1.12 which is the limit value of the optical steepness of the liquid crystal display shown in the document “High-speed liquid crystal technology” (page 63, published by CMC Corporation).
It shows the same value as. Therefore, it can be understood that it is useful for high time division driving.

(Embodiment 5)

[0063]

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The nematic liquid crystal composition No. 3-
5 was prepared and the properties of this composition were measured. The results were as follows. T _NI : 80.1 ° C. T → _N : −30. ° C _Vth : 1.98 V γ: 1.12 Δε: 7.7 Δn: 0.144 η: 11.9 c. p.

The nematic liquid crystal composition has a limit value of 1.12 which is the limit value of the optical steepness of the liquid crystal display shown in the document “High-speed liquid crystal technology” (p. 63, published by CMC Corporation).
It shows the same value as. Therefore, it can be understood that it is useful for high time division driving.

When the response speed at a low temperature was measured, a liquid crystal display device showing 167 msec at -20 ° C. was obtained.

(Embodiment 6)

[0068]

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The nematic liquid crystal composition No. 3-
6 were prepared, and various properties of the composition were measured. The results were as follows. T _NI : 76.0 ° C. T → _N : −30. ° C _Vth : 1.66 V Δε: 9.7 Δn: 0.120 η: 13.2 c. p.

A chiral substance “S-811” (manufactured by Merck) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal. On the other hand, "San Ever
An alignment film was formed by rubbing an organic film of "610" (manufactured by Nissan Chemical Industries, Ltd.) to produce an STN-LCD display cell having a twist angle of 220 degrees. The mixed liquid crystal was injected into this cell to construct a liquid crystal display, and the display characteristics were measured. As a result, a liquid crystal display device exhibiting STN-LCD display characteristics with excellent high time division characteristics and improved fast response was obtained. In addition, the chiral substance is the intrinsic helical pitch P of the mixed liquid crystal by adding the chiral substance.
And the cell thickness d of the display cell is Δn · d = 0.85, d /
It was added so that P = 0.53.

(Embodiment 7)

[0072]

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A nematic liquid crystal composition No. 3-
7 were prepared, and various properties of the composition were measured. The results were as follows. T _NI : 71.9 ° C. T → _N : −30. ° C _Vth : 2.20 V Δε: 4.2 Δn: 0.090 η: 10.9 c. p.

When the response speed at low temperature was measured, -2 was obtained.
A liquid crystal display showing 136 msec at 0 ° C. was obtained.

(Embodiment 8)

[0076]

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The nematic liquid crystal composition No. 3-
8 and the properties of this composition were measured. The results were as follows. T _NI : 100.0 ° C. T → _N : −70. ° C. V _th : 1.79 V Δε: 6.8 Δn: 0.097 η: 19.8 c. p. Voltage holding ratio before test: 99.1% Voltage holding ratio after heating acceleration test: 98.2%

Since the nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, it can be understood that the composition is thermally stable. Further, when an active matrix liquid crystal display device using this composition as a constituent material was produced, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.

(Embodiment 9)

[0080]

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The nematic liquid crystal composition No. 3-
9 were prepared, and various properties of the composition were measured. The results were as follows. T _NI : 80.1 ° C. T → _N : −70. ° C _Vth : 1.36 V Δε: 9.5 Δn: 0.130 η: 22.4 c. p. Voltage holding ratio before test: 99.1% Voltage holding ratio after heating acceleration test: 98.1%

Since the nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, it can be understood that the composition is thermally stable. Further, when an active matrix liquid crystal display device using this composition as a constituent material was produced, it was confirmed that the device was excellent in that the leakage current was small and flicker did not occur.

[0083]

The nematic liquid crystal composition of the present invention has a T
_Lowers T → _N without lowering _NI , has excellent high-speed response due to the viscosity reducing effect, shows a nematic phase over a wide temperature range, has high voltage holding ratio, and has high chemical stability It is clear that. Therefore, the nematic liquid crystal composition of the present invention has an active matrix form,
The present invention can be used for a twisted nematic or super twisted nematic liquid crystal display device. Also, in combination with a compound having a large birefringence,
Since a liquid crystal material having a large birefringence can be adjusted without impairing the above effects, it is possible to provide a liquid crystal display element that performs color display with the birefringence of a liquid crystal layer and a retardation plate.

Claims (15)

[Claims] 1. A compound of the general formula (I) (Wherein, R ¹¹ and R ¹² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p and q each independently represent an integer of 0 to 4). A liquid crystal component A containing at least one compound represented by the following formula and a liquid crystal component B containing at least two compounds having a dielectric anisotropy of +2 or more.
A liquid crystal material having a dielectric anisotropy of 3 or more, a nematic phase of 60 ° C. or more, an isotropic liquid phase transition temperature, and a crystal phase or a smectic phase of 0 ° C. or less. A nematic liquid crystal composition having a nematic phase transition temperature. 2. The liquid crystal component A contains at least one compound of the general formula (I) wherein R ¹¹ and / or R ¹² is a hydrogen atom. 2. The nematic liquid crystal composition according to 1. 3. The liquid crystal component A contains at least one compound characterized by the general formula (I) wherein n is represented by an integer of 0, 2 or 4. Item 3. The nematic liquid crystal composition according to item 1 or 2. 4. The liquid crystal material according to claim 1, wherein the liquid crystal component A is 1 to 4.
4. The nematic liquid crystal composition according to claim 1, wherein the composition comprises 40% by weight. 5. The liquid crystal component B represented by the following general formula (II-1):
(II-3) (Wherein, R ^{21 to} R ²³ each independently represent a straight-chain alkyl group or alkenyl group having 2 to 7 carbon atoms or C _s H _{2s + 1} -O-C _t
Represents H _2t, s and t are each independently an integer of 1~5, X ²¹ ~X ²³ each independently is F, Cl, -OCF _3, -O
CHF _2, represents -CF ₃ or -CN, Y ²¹ ~Y ²⁹ each independently represent a hydrogen atom or a fluorine atom, Z ^{2 1} ~Z ²³ each independently represents a single bond, -COO -, - C ₂ H ₄ — or —C ₄ H ₈ —, Z ²¹ may also be —C≡C— or —CH ＝ CH—, and Z ²⁴ and Z ²⁵ each independently represent a single bond, —COO -Or-
Represents CｍC-, l and m each independently represent 0 or 1, and the hydrogen atom (H) of the cyclohexane ring in each compound may be substituted with a deuterium atom (D). )
5. The nematic liquid crystal composition according to claim 1, comprising at least two compounds selected from the group consisting of compounds represented by the formula: 6. The liquid crystal component B represented by the following general formula (II-1):
In (II-3), R ^{twenty one}~ R^{twenty three}Are each independently a carbon atom
At least a compound represented by an alkenyl group of Formulas 2 to 7
The nema according to claim 5, wherein the nema contains at least one kind.
Tic liquid crystal composition. 7. The liquid crystal component B represented by the general formula (II-1):
In (II-3), X ^{twenty one}~ X^{twenty three}Are independently F and C
1, -OCF_ThreeOr at least a compound represented by -CN
7. The composition according to claim 5, wherein one or more kinds are contained.
Nematic liquid crystal composition. 8. The liquid crystal material according to claim 1, wherein
Claims 1 and 2 characterized by the above-mentioned.
8. The nematic liquid crystal composition according to 3, 4, 5, 6, or 7. 9. The liquid crystal component B represented by the following general formula (II-1):
9. The nematic liquid crystal composition according to claim 5, which comprises 1 to 100% by weight of the compound (II-3). 10. The liquid crystal material contains a liquid crystal component C,
The liquid crystal component C has a general formula (III-1) to (III-3): (Wherein, R ^{31 to} R ³³ each independently represent a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^{34 to} R ³⁶
Are each independently a linear alkyl group having 1 to 7 carbon atoms,
Alkoxy group, an alkenyl group, an alkenyloxy group or _{C u H 2u + 1 -O-} C v t H 2v, u and v are each independently an integer of 1 to 5, Y ³¹ to Y ³⁴ each Independently H,
F or CH ₃ , Z ^{31 to} Z ³⁴ each independently represent a single bond, —COO—, —C ₂ H ₄ — or —C ₄ H ₈ —, and Z ³¹ also represents —C≡C— or —CH ＝ CH—, Z ³⁵ represents a single bond, —C≡C— or —COO—; ring A ³¹ and ring A ³² each independently represent a cyclohexane ring or a cyclohexene ring; , J and k each independently represent an integer of 0 or 1, and the hydrogen atom (H) of the cyclohexane ring in each compound may be substituted with a deuterium atom (D). )
The nematic liquid crystal composition according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, and 9 comprising a compound selected from the group of compounds represented by 11. The liquid crystal material according to claim 10, wherein said liquid crystal component C contains at most 75% by weight.
The nematic liquid crystal composition according to the above. 12. The liquid crystal material has a dielectric anisotropy of 4 to 25, a nematic phase of 70 ° C. or higher, an isotropic liquid phase transition temperature, and a crystal phase or smectic phase of −10 ° C. or lower. The nematic liquid crystal composition according to any one of claims 1 to 11, wherein the composition has a nematic phase transition temperature. 13. The liquid crystal material has a birefringence of 0.07.
The nematic liquid crystal composition according to any one of claims 1 to 12, wherein the composition is in the range of 0.16 to 0.16. 14. An active matrix liquid crystal display using the nematic liquid crystal composition according to claim 1. Description: 15. A twisted nematic or super twisted nematic liquid crystal display using the nematic liquid crystal composition according to claim 1.