JPH1077475A - Nematic liquid crystal composition and liquid crystal display made by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nematic liquid crystal composition having a wide drivable temperature range for the size of a desired birefringence and excellent in response characteristics by blending two specified liquid crystal components. SOLUTION: This composition consists of 5 to 40 compounds and contains the following liquid crystal components A and B: one or more compounds (A) represented by formula I (wherein R11 is a 1-10C linear alkyl or alkoxy; and X11 is a 1-10C alkyl, alkoxy, F, Cl, or CN); and one or more compounds (B) selected from those represented by formulas II-1 to II-4 [wherein R21 to R24 are each independently a 2-20C linear alkyl or alkenyl or Cs H2s+1 -O-Ct H2t (wherein s and t are each 1 to 5); Y<21> to Y<25> and W<21> to W<23> are each independently H or F; Z<21> is a single bond, COO or C2 H4 ; and the hydrogen atom H of the cyclohexane ring in formula II-1 may be substituted by a deuterium atom D].

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. As such a liquid crystal material, the elastic constant ratio K ₃₃ / K ₁₁ is around 1.5, and the dielectric constant anisotropy and viscosity are relatively small.
In particular, those having a large birefringence are required. In addition, in order to achieve a brighter display and a higher contrast ratio, a new reflective color liquid crystal display system using the birefringence of liquid crystal and a retardation plate instead of the color filter layer [Television Society Technical Report vol. 14 No10.p.51 1990] and a liquid crystal display device having a reflective surface with a small parabolic surface on the substrate electrode side has been proposed. As a liquid crystal material suitable for this, a birefringence index characteristic that causes a larger phase difference due to a difference in light wavelength and an optical characteristic of a birefringence index that maintains a high contrast even at a wide viewing angle are required. Further, a liquid crystal display device having a wider operating temperature is required for display applications such as miniaturization, portability, and increase in the number of pixels. As a liquid crystal material suitable for this, the elastic constant K ₁₁ is 10
There is a demand for a material having a nematic temperature in a range of from 25 to 25, which is chemically stable, can efficiently reduce the response speed, and has a wider nematic temperature. As described above, there is a need to comprehensively optimize the individual physical properties of the liquid crystal material, and proposals for new liquid crystal compounds or liquid crystal compositions are still required.

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 Digest,
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 on a new liquid crystal compound or liquid crystal composition, for example, Japanese Patent Application Laid-Open No. Hei 6-312949 and Japanese Patent Application Laid-Open No. 5-501735.

[0005]

In order to improve the liquid crystal display characteristics as described above, a liquid crystal material having a desired birefringence is required. There is also a need for higher chemical stability of the liquid crystal material, lower viscosity, high-speed response of the liquid crystal display, and a wider driving temperature range. The technology relating to the compound of the general formula (I) and the analogous compound thereof according to the present invention includes:
For example, as mentioned in JP-A-54-87688, the knowledge of a mixture containing the compound of the general formula (I) is as follows.
There have not been enough reports yet. Also, TN as described above
-Liquid crystal material properties or mixtures having adjusted desired birefringence, dielectric anisotropy, elastic constant, etc. useful for LCD, STN-LCD, TFT-LCD have not yet been reported.

In detail, Japanese Patent Application Laid-Open No. 54-87688 discloses, as compounds having a positive dielectric anisotropy, compounds represented by the following general formulas (a-1) to (a-2).

[0007]

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A liquid crystal compound represented by the formula (wherein, R represents an alkyl group) is used. When these compounds were used, even if the temperature of the nematic phase could be broadened, the characteristics were insufficient in response.
In addition, because of an excessively large birefringence, a liquid crystal material useful for STN-LCDs that particularly emphasizes the birefringence effect has not been obtained.

An object of the present invention is to solve or further improve the above-mentioned problem, and a wide temperature range in which a desired birefringence index can be driven is provided.
An object of the present invention is to provide a nematic liquid crystal composition having excellent responsiveness, and using this liquid crystal composition as a constituent material, a liquid crystal display device such as a TN-LCD, an STN-LCD, and a TFT-LCD having improved electro-optical characteristics. Is to provide.

[0010]

According to the present invention, there is provided a liquid crystal composition comprising 1.5 to 40 compounds, wherein the liquid crystal composition has the general formula (I)

[0011]

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(Wherein R ¹¹ represents a linear alkyl group or alkoxy group having 1 to 10 carbon atoms, and X ¹¹ represents a linear alkyl group or alkoxy group having 1 to 10 carbon atoms, F, C
represents 1 or -CN. ), One or more compounds represented by general formulas (II-1) to (II)
-Four)

[0013]

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(Wherein, R ^{21 to} R ²⁴ each independently represent a straight-chain alkyl group, alkenyl group or C 2-10 carbon atom);
represents _{s H 2s + 1 -O-C} t H 2t, s and t are each independently 1
And Y ^{21 to} Y ²⁵ each independently represent a hydrogen atom or a fluorine atom; W ^{21 to} W ²³ each independently represent a hydrogen atom or a fluorine atom; Z ²¹ represents a single bond; COO- or -C ₂ H ₄ - represents the general formula (II-1) in cyclohexane hydrogen atoms of the ring (H) may be substituted with deuterium atoms (D). A nematic liquid crystal composition comprising a liquid crystal component B consisting of one or more compounds selected from the group of compounds represented by (1). 2. 2. The nematic liquid crystal composition according to the above item 1, wherein the liquid crystal component A contains 30 to 100% by weight of a compound in which X ¹¹ in the general formula (I) is a fluorine atom. 3. The liquid crystal component A is a compound in which R ¹¹ is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group in the general formula (I), and / or X ¹¹ is a methyl group, an ethyl group, or a propyl group. 3. The nematic liquid crystal composition according to the above 1 or 2, wherein the composition contains 30 to 100% by weight of a compound represented by a butyl group or a pentyl group. 4. 4. The nematic liquid crystal composition according to the above item 1, 2 or 3, wherein the liquid crystal composition contains 1 to 50% by weight of the liquid crystal component A. 5. The liquid crystal component B is a compound represented by the general formula (II-1), wherein R ²¹ is a compound represented by an alkyl group or an alkenyl group having 2 to 5 carbon atoms, and / or Z ²¹ is a single bond;
-COO- or -C ₂ H ₄ - 10~100 a compound represented by
1, 2, 3 or 4 above by weight.
The nematic liquid crystal composition according to the above. 6. Said liquid crystal component B, in the compound of formula (II-2), compound R ²² is represented by an alkyl group having 2 to 5 carbon atoms, and / or ^{Y 23, Y 24, W 21} , W 22 A compound in which at least one of
6. The nematic liquid crystal composition according to the above 1, 2, 3, 4 or 5, characterized in that the composition contains 1% by weight. 7. The liquid crystal component B is a compound represented by the formula (II-3), wherein R ²³ is a compound represented by an alkyl group having 2 to 5 carbon atoms, and / or at least one of Y ²⁵ and W ²³ is a fluorine atom. 7. The nematic liquid crystal composition according to the above 1, 2, 3, 4, 5 or 6, comprising 10 to 100% by weight of a compound represented by the formula: 8. (1) wherein the liquid crystal component B contains 10 to 100% by weight of a compound represented by the formula (II-4), wherein R ²⁴ is an alkyl group having 3 to 8 carbon atoms. 8. The nematic liquid crystal composition according to 2, 3, 4, 5, 6, or 7. 9. 9. The nematic liquid crystal composition according to any one of the above items 1 to 8, wherein the liquid crystal composition contains 10 to 90% by weight of the liquid crystal component B. 10. The liquid crystal composition has a general formula (III-1) to (III-3)

[0015]

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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 a 1 to 7 carbon atom. 7 represents a linear alkyl group, an alkoxy group, an alkenyl group, or an alkenyloxy group, and Y ³¹ represents a hydrogen atom, a fluorine atom or-
Represents CH _3, Y ³² and Y ³³ are each independently represent a hydrogen atom or a fluorine atom, Z ³¹ to Z ³³ each independently represents a single bond, -COO- or -C ₂ H ₄ - represents, Z ³⁴ is a single bond, -C
≡C- or -COO-, ring A ³¹ represents a cyclohexane ring or a cyclohexene ring, n ¹ and n ² each independently represent an integer of 0 or 1, and a hydrogen atom (H ) May be substituted by a deuterium atom (D). (1) containing a liquid crystal component C composed of one or more compounds.
10. The nematic liquid crystal composition according to any one of items 9 to 9. 11. The liquid crystal component C is a compound represented by the formula (III-1), wherein R ³¹ is a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and / or R ³⁴
Is a compound represented by a linear alkyl group or an alkoxy group having 1 to 5 carbon atoms, and / or Z ³¹ is a single bond or -C
(11) The nematic liquid crystal composition as described in (10) above, which contains 10 to 100% by weight of a compound represented by OO-. 12. The liquid crystal component C is a compound represented by the general formula (III-2), wherein R ³² is a compound represented by a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and / or R ³⁵
Is a compound represented by a linear alkyl group or an alkoxy group having 1 to 5 carbon atoms, and / or Z ³² is a single bond, -CO
A compound represented by O— or —C ₂ H ₄ —, and / or a ring A ³¹
Contains 10 to 100% by weight of a compound represented by a cyclohexane ring. 13. The liquid crystal component C is a compound represented by the formula (III-3) wherein Z ³⁴ is represented by —C≡C—
The above-mentioned 10, 11 characterized by containing 100% by weight.
Or the nematic liquid crystal composition according to 12. 14． The liquid crystal composition contains the liquid crystal component C at most 7
The above-mentioned 10, 11, 1 characterized by containing 0% by weight.
14. The nematic liquid crystal composition according to 2 or 13. 15. The liquid crystal composition is a compound having a core structure having four six-membered rings, and one or more compounds having a liquid crystal phase-isotropic liquid phase transition temperature of 100 ° C. or higher. 15. The nematic liquid crystal composition as described in any one of 1 to 14 above, which comprises: 16. The liquid crystal composition has a dielectric anisotropy of 4 to 30, a birefringence of 0.08 to 0.33, a nematic phase-isotropic liquid phase transition temperature of 70 ° C. or more, 10
16. The nematic liquid crystal composition according to any one of the above items 1 to 15, wherein the composition has a crystalline phase or a smectic phase-nematic phase transition temperature of not more than ° C. 17． The liquid crystal composition has an induced helical pitch of 0.5 to 1
17. The nematic liquid crystal composition according to any one of the above 1 to 16, further comprising a compound having an optically active group having a thickness of 000 μm. 18. 18. A twisted nematic or super twisted nematic liquid crystal display using the nematic liquid crystal composition according to the above item 17. 19. 19. The liquid crystal display device according to the above item 18, wherein the liquid crystal layer has a thickness of 1 to 30 μm. Was found as a means for solving the above problem.

[0017]

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 liquid crystal composition of the present invention contains a liquid crystal component A comprising a compound represented by the general formula (I) as an essential component. The liquid crystal component A has a relatively low viscosity, a larger birefringence, and a larger elastic constant. For this reason, the liquid crystal composition of the present invention can adjust the birefringence and the elastic constant in a wide range, and has a feature that it can be driven, for example, at a high speed. The liquid crystal composition of the present invention comprises a liquid crystal component A consisting of a compound of the general formula (I) 1 to
It has been found that by containing 50% by weight and containing 10 to 90% by weight of the liquid crystal component B composed of the compounds represented by the general formulas (II-1) to (II-4), a faster response characteristic is obtained. . In addition, the liquid crystal component A has other characteristics, such as, when mixed with a liquid crystal material, improves the nematic phase-isotropic liquid phase transition temperature to a relatively high temperature and has excellent compatibility. Can be made wider. Furthermore, it has relatively small dielectric anisotropy and higher chemical stability.

From such a viewpoint, a more preferred form of the compound represented by the general formula (I) is a compound wherein R ¹¹ is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group, And / or X ¹¹ is a compound represented by F, a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. Specifically, the general formulas (I-1) to (I
-8) is more preferable, and the liquid crystal component A is
At least one kind of such a compound is used in an amount of 30 to 100.
A nematic liquid crystal composition containing by weight gave favorable results. In addition, each compound was used after removing impurities by a method such as distillation, column purification, recrystallization, etc. and sufficiently purified.

[0020]

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One or more compounds of the general formula (I) can be contained as the liquid crystal component A. Even if one kind is used, the above-mentioned effects can be obtained. The liquid crystal composition of the present invention containing a liquid crystal component A containing at least one compound of the present invention can be used for a liquid crystal display device such as a TN-LCD or an STN-LCD using the liquid crystal component A as an improved electro-optical device. In particular, characteristics such as responsiveness at low temperatures, steepness, and temperature dependence of driving voltage are made more preferable.

The liquid crystal composition of the present invention contains, in addition to the above liquid crystal component A, a liquid crystal component B composed of compounds represented by formulas (II-1) to (II-4). These compounds are liquid crystal compounds having a dielectric anisotropy of greater than 5, whereby 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. be able to.

The liquid crystal component B may be composed of one type of compound, and preferably has a range of 3 to 15 types. A compound of the general formula (II-1) having a dielectric anisotropy of +8 to +17;
25 to +60 compounds of the general formula (II-2), +10 to +2
It is preferable to appropriately select from the compounds of the general formula (II-3) of No. 5 and the compounds of the general formulas (II-4) of +18 to +30 and to obtain predetermined drive voltage and response characteristics.
In this case, the compounds of the general formula (II-1) are preferably mixed in at most 8 types, and the compounds of the general formula (II-2) are preferably mixed in at most 10 types or less. It is preferable that the compounds of the general formula (II-3) are mixed in at most 8 kinds or less, and the compounds of the general formula (II-4) are mixed in at most 6 kinds or less.
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, it is preferable that the temperature dependency such as the driving voltage, the contrast relating to the steepness, and the response is more preferable.

The liquid crystal component B of the present invention has the general formula (II-
Among the compounds represented by 1) to (II-4), the compound may be composed of a compound selected from one kind of general formula, or may be composed of a plurality of general formulas. In this case, the compound of each formula is preferably contained in the range of 10 to 100% by weight. Particularly preferred and more specific compounds represented by formulas (II-1) to (II-4) include compounds represented by formulas (II-1a) to (II-4)
c) is shown below. In addition, each compound was used after removing impurities by a method such as distillation, column purification, recrystallization, etc. and sufficiently purified. The liquid crystal component B containing these compounds has a feature of being well mixed with the liquid crystal component A, which is an essential component, and is particularly useful for adjusting the drive voltage according to the purpose and improving its temperature dependence or response. is there. In particular, the general formulas (II-1a) to (II-1c) and the general formulas (II-2a) to (II-4c)
Is excellent in this effect, and this effect can be obtained even with a small content of 1 to 25%.

[0025]

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[0026]

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(In the formula, R ^{21 to} R ²³ represent the same meaning as described above.)

Further preferred embodiments will be described in detail. R ²¹ is an alkyl group having 2 to 5 carbon atoms or CH ₂ =
A compound which is an alkenyl group of CH- (CH ₂ ) _p (p = 0, 2) is preferable, and compounds of the general formulas (II-1a) to (II-1c) preferably have this group. It is particularly preferable to include at least one or more compounds having an alkenyl group in the compound, and the viscosity and viscoelasticity can be reduced. Similarly, R ^{22 is} also preferably an alkyl group having 2 to 5 carbon atoms, and the above-mentioned compound in which p is an alkenyl group having 2, 4 is preferable. Compounds of the general formulas (II-2a) to (II-2f) are preferably It is preferable to have In order to improve the temperature characteristics of the drive voltage, especially at low temperatures, Y ²³ , Y ²⁴ , W ²¹ ,
It is particularly preferred that at least one of W ²² contains a compound represented by F. R ²³ is preferably an alkyl group having 2 to 5 carbon atoms or a compound in which the above-mentioned p is an alkenyl group having 2,4, and the compounds of the general formulas (II-3a) to (II-3c) have this group. Is preferred. R ²⁴ can be an alkyl group having 2 to 10 carbon atoms, but is preferably a compound having 4 to 7 carbon atoms.

When a smaller birefringence is required,
It is preferable to frequently use the compounds of the general formulas (II-1a) to (II-1g) for the liquid crystal component B. When a higher birefringence is required, the compounds of the general formulas (II-3a) to (II-4c) It is preferred that the compound of the formula (1) is frequently used in the liquid crystal component B. When a lower driving voltage is required, the compounds of the general formulas (II-1) to (II-3) in which at least one of Y ²¹ to Y ²⁵ and W ^{21 to} W ²³ is F are
More than one kind is preferably contained in the liquid crystal component B.

A compound in which the hydrogen atom (H) in the cyclohexane ring of the general formula (II-1) is replaced with a deuterium atom (D) can be used. This compound adjusts the elastic constant of the liquid crystal composition. It is preferable to contain at least one compound substituted with a deuterium atom (D) because it is useful for adjusting the pretilt angle corresponding to the orientation film and the alignment film.

The effect of the liquid crystal component B described above can be obtained even when the content of the liquid crystal component C described later is very small. For the purpose of particularly lowering the driving voltage, the content of the liquid crystal component C can be reduced to 10% by weight or less. In this case, it is preferable to reduce the viscosity of the liquid crystal component C as much as possible, and the drive voltage is hardly increased or stays in a small range, so that the response speed can be efficiently improved. For example, when the amount of the liquid crystal component C is small, as a method of achieving this effect by the liquid crystal component B, a compound of the general formula (II-1a) or the compound of the general formula (II-3a) is used. Is preferably contained.

The liquid crystal composition of the present invention comprises, in addition to the essential liquid crystal components A and B, a compound represented by the following general formula (III-1):
A liquid crystal component C comprising the compound of (III-3) at most 70
It is preferred that the content be contained by weight. The liquid crystal component C is preferably composed of at least one type and at most 20 types, and more preferably at least two types and at most 12 types.

The liquid crystal component C of the present invention has the general formula (III-
As particularly preferred compounds represented by 1) to (III-3),
The general formulas (III-1a) to (III-3h) are shown below. The liquid crystal component C containing these compounds had a feature of being well mixed with the liquid crystal component A containing the compound of the general formula (I), and was useful for improving a low temperature nematic phase.

[0034]

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[0035]

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(In the formula, R ^{31 to} R ³⁶ and Y ^{31 to} Y ³³ have the same meanings as described above.)

As the liquid crystal component C, general formulas (III-1) to (I
By containing the compound of II-3), the viscosity and viscoelasticity can be reduced, and the specific resistance and the voltage holding ratio are relatively high. The viscosity of the liquid crystal component C is preferably as low as possible, and in the case of the present invention, 45 cp
Or less, more preferably 30 cp or less, and 20 c
p or less is more preferable, and 15 cp or less is particularly preferable.
Further, R ³¹ to R ³³ is a linear alkyl group or a _{CH 2 = CH- (CH 2)} 2~5 carbon atoms _{q (q} = 0,2) at least one kind of compound is an alkenyl group-containing Liquid crystal component C obtained a more favorable effect. More particularly, compounds of the general formulas (III-1a), (III-1d), (III-2a) to (III-2c), and compounds of the general formulas (III-3c) to (II-3) wherein Y ³¹ is a hydrogen atom
This effect can be obtained even when the compound of I-3f) is contained in a small amount of 3 to 30%, and is useful for improving the response speed.
For example, it is useful for STN-LCD.

Due to the above-mentioned effects, a more preferable compound to be contained in the liquid crystal component C is a compound represented by the general formula (III-1) wherein R ³¹ is a linear alkyl group having 2 to 5 carbon atoms or Represents an alkenyl group, wherein R ³⁴ has 1 to 4 carbon atoms
A compound represented by a linear alkyl group, an alkoxy group, an alkenyl group, or an alkenyloxy group of the general formula (II
In the compound of I-2), R ³² represents a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and R ³⁵ represents a linear alkyl group, alkoxy group or alkenyl having 1 to 4 carbon atoms. And a compound represented by an alkenyloxy group.

The liquid crystal component C of the present invention has the general formula (III-
1), the compounds represented by the general formula (III-2) and the general formula (III-3) can be each independently constituted, but the compounds represented by the general formula (II
Use of a compound represented by I-1) and / or a compound represented by formula (III-2) in combination with a compound represented by formula (III-3), particularly a compound wherein Z ³⁴ is represented by -C≡C- Thereby, the birefringence of the liquid crystal composition can be easily optimized according to the application. By frequently using the compounds of the general formulas (III-1) and (III-2), for example, the compounds of the above general formulas (III-1a) to (III-2f), the birefringence can be reduced. Can,
It is possible to easily achieve reduction in color unevenness, improvement in viewing angle characteristics, and increase in contrast ratio of the liquid crystal display device. Further, a compound of the general formula (III-3), for example,
By frequently using the compounds a) to (III-3h), the birefringence can be increased, and a thin liquid crystal display device having a liquid crystal layer having a thickness of 1 to 5 μm can be manufactured.

When the liquid crystal composition of the present invention is intended to have a quicker response to the magnitude of the driving voltage, the following can be achieved. When a medium drive voltage is intended, the liquid crystal composition of the present invention has a dielectric anisotropy in the range of 3 to 15 and a viscosity at 20 ° C. of 8 to 20 c. p. Is preferably within the range. In this case, the viscosity of only the liquid crystal component C is 25c. p. The following is preferred, and 15c. p. The following is more preferable, and 10c. p. The following are particularly preferred.
When a particularly low driving voltage is intended, the dielectric anisotropy of the liquid crystal composition of the present invention is preferably in the range of 15 to 30, and particularly preferably in the range of 18 to 28.

At present, a polyimide-based alignment film used for TN-LCD, STN-LCD or TFT-LCD is often used. For example, LX1400, SE150, SE610, AL1051, AL34
08 etc. are used. The liquid crystal display characteristics, display quality, reliability, and productivity are closely related to the specification of the alignment film. For example, the pretilt angle characteristics are important for the liquid crystal material. The magnitude of the pretilt angle needs to be adjusted appropriately in order to obtain desired liquid crystal display characteristics and uniform orientation. For example, when the pretilt angle is large, an unstable alignment state is likely to occur, and when the angle is small, sufficient display characteristics are not satisfied.

The present inventors have found that the pretilt angle is larger.
See that there is a separation between liquid crystal materials and smaller liquid crystal materials.
It can be used to obtain the desired liquid crystal.
Achieving display characteristics and uniform alignment from liquid crystal materials
Was found. This technique can be applied to the present invention. An example
For example, the liquid crystal component B contains the general formulas (II-1) to (II-4).
If it is, it will be as follows. Larger pretilt angle
Is R^{twenty one}Is an alkenyl group, Y^{twenty one}, Y^{twenty two}Is a hydrogen atom
A compound of the general formula (II-1)^{twenty three}Is an alkyl group, W ^{twenty three}, Y
^{twenty five}Is a hydrogen atom, the content of the compound of the general formula (II-3)
The smaller the pretilt angle, which is obtained by increasing
R^{twenty one}Is an alkyl group, Y^{twenty one}, Y^{twenty two}Is the general formula (II-1) of F
Compounds, compounds of general formulas (II-2) and (II-4), especially Y^{twenty three}
And / or Y^{twenty four}Is the content of the compound of the general formula (II-2) wherein F is
Can be obtained by increasing General formula (II-1) or general formula
Hydrogen of cyclohexane ring in (III-1) and (III-2)
Field of compound in which atom (H) is replaced by deuterium atom (D)
The pre-tilt angle
Make adjustment possible. Such effects are, for example, greater
When a pretilt angle is obtained, the compound described above is used in a liquid crystal composition.
10 to 40% by weight or more based on the total amount
It can be almost obtained by doing.

The technology relating to the compound of the general formula (I) according to the present invention is described, for example, in JP-A-54-87688, and includes, for example, the compounds of the general formulas (a-1) and (a-2). Is shown. It is also useful for compatibility and response characteristics. However, Japanese Patent Application Laid-Open No. 54-876
The composition disclosed in Japanese Patent Publication No. 88 has a problem in responsiveness, and requires an improvement measure. For example, the response characteristics of TN-LCDs are currently required to be 60 msec or less, preferably 50 msec or less, more preferably 40 msec or less, and particularly preferably 30 msec or less, and need improvement. In particular, the compounds of the general formulas (a-1) and (a-2) tend to deteriorate the response characteristics, and require new improvement means.

The present invention has solved the above-mentioned problems, and in detail, for example, each of the following individual measures:
(1) The liquid crystal component A is not excessively used, and the content is 50% by weight.
(2) When the content of the liquid crystal component A is particularly large, the number of compounds constituting the liquid crystal component B is four or more.
(3) The liquid crystal component B contains at least one compound having a cyclohexane ring. (4) The liquid crystal component B has a general formula (II-
2) When the compound of (II-3) is contained, the compound represented by the general formula (II-
(5) When the content of the liquid crystal component A is particularly large, the liquid crystal component C is used together, and (6) The liquid crystal component B is represented by the general formula (II-2) and / or (II-3). )), It has been found that a liquid crystal component C is used even in a trace amount. In the case of the above (3), a more preferable result is exhibited by including the compound of the general formula (II-1) in the liquid crystal component B, and in the above (6), the liquid crystal component C has a general formula (III-1) ) To (III-3) showed more preferable results.

The content of each liquid crystal component in the nematic liquid crystal composition of the present invention can be as follows. Liquid crystal component A
Is in the range of 1 to 50% by weight, preferably in the range of 3 to 40% by weight. The liquid crystal component B is in the range of 10 to 90% by weight, preferably in the range of 25 to 90% by weight.
More preferably, it is in the range of 80% by weight. The content of the liquid crystal component C is at most 70% by weight, preferably 3 to 65% by weight, more preferably 5 to 60% by weight,
The range is more preferably from 10 to 55% by weight. General formula (I)
The content of the compound represented by the formula (I) is preferably less than 20% by weight alone, and more than that is preferably composed of two or more kinds, and represented by the general formulas (I-1) to (I-8). The content of the compound with respect to the liquid crystal component A is in the range of 50 to 100% by weight, preferably in the range of 70 to 100% by weight. The content of the compounds represented by the general formulas (II-1) to (II-4) or the compounds represented by the general formulas (II-1a) to (II-4c) is as follows:
It is preferably 30% by weight or less by itself, more preferably 25% by weight or less, and more preferably 25% by weight or more. The content of the compounds represented by formulas (II-1a) to (II-4c) with respect to the liquid crystal component B is in the range of 10 to 100% by weight, preferably in the range of 50 to 100% by weight.
The range of 5 to 100% by weight is more preferable. General formula (III-
Compounds represented by 1) to (III-4) or the general formula (III-
The content of the compounds represented by 1a) to (III-3h) is preferably 30% by weight or less, more preferably 25% by weight or less, and more preferably 2 or more kinds.
The content of the compounds represented by formulas (III-1a) to (III-3h) with respect to the liquid crystal component C is in the range of 10 to 100% by weight, preferably in the range of 50 to 100% by weight.
The range of 75 to 100% by weight is more preferable.

The crystalline phase or the smectic phase-nematic phase transition temperature is preferably -10 ° C or lower, more preferably -20 ° C or lower, particularly preferably -30 ° C or lower. The nematic phase-isotropic liquid phase transition temperature is 60 ° C. or higher, preferably 70 ° C. or higher, and more preferably 80 ° C. to 130 ° C.
Range. The liquid crystal composition of the present invention requires a dielectric anisotropy of 3 or more, preferably in the range of 4 to 40, and in the case of emphasizing high-speed response, the range of 4 to 16 requires a lower driving voltage. If so, the range of 17 to 30 is preferable.
The smaller or medium birefringence is 0.08 or more.
A range of less than 18 is preferred, and a larger birefringence is
The range is preferably from 0.18 to 0.33. The properties of such a nematic liquid crystal composition include an active matrix type, a twisted nematic or a super nematic.
It is useful for a twisted nematic liquid crystal display device.

The above nematic liquid crystal composition is useful for a TN-LCD or STN-LCD having a high response speed, and a color display can be obtained by using the birefringence of 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 °. For this reason, the liquid crystal composition of the present invention has an induced helical pitch of 0.5 to 0.5.
A compound having an optically active group having a thickness of 1000 μm can be contained. 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 30 ° to 100 °.
In the case of °, a pretilt angle of 1 ° to 4 ° is preferable, and 100 °
At ~ 180 °, a pretilt angle of 2 ° to 6 ° is preferable,
A pretilt angle of 3 ° to 12 ° is preferable at 180 ° to 260 °, and a pretilt angle of 6 ° to 20 ° is preferable at 260 ° to 360 °.

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.

[0049]

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 put in an ampoule tube, degassed in vacuum, sealed with nitrogen replacement, and subjected to a heating acceleration test at 150 ° C. for 1 hour to measure the specific resistance 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 constructing a TN-LCD having a cell thickness of 6 μm Γ: ratio of saturation voltage (Vsat) to Vth Δε: dielectric anisotropy Δn: birefringence η: viscosity at 20 ° C. (cp)

(Example 1)

[0053]

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A nematic liquid crystal composition (2-1) was prepared, and various properties of the composition were measured. The results were as follows. T _NI : 93.6 ° C. T → _N : -1. ° C. V _th : 2.59 V γ: 1.15 Δε: 4.9 Δn: 0.281

Using this nematic liquid crystal composition, a TN-LCD having a cell thickness d of 1.8 μm was constructed and its display characteristics were measured. As a result, the threshold voltage was 2.28 V and the response speed was 1.1 msec. Was obtained.

When the wavelength dispersion of the birefringence of the nematic liquid crystal composition was measured, the ratio at 400 nm to the light wavelength of 650 nm was 1.15 or more. Because this liquid crystal material shows a larger phase difference due to the difference in the wavelength of light, a new reflective color that uses the birefringence of the liquid crystal and the phase difference plate to perform color display without using a color filter layer It can be understood that it is useful for a liquid crystal display system.

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. 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.

(Example 2)

[0059]

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A nematic liquid crystal composition (2-2) was prepared, and various characteristics of the composition were measured. The results were as follows. T _NI : 67.3 ° C. T → _N : −70. ° C V _th : 1.85 V γ: 1.12 Δε: 6.6 Δn: 0.145 η: 24.1 c. p. Specific resistance before test: 6.0 × 10 ¹¹ Ω
cm Specific resistance after heating acceleration test: 4.3 × 10 ¹¹ Ω ·
cm

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).
And the same values as in the above, and it can be understood that this liquid crystal composition is useful for high time division driving.

Since the nematic liquid crystal composition has a high specific resistance after the heat acceleration test, it can be understood that it is stable to heat. Further, a new nematic liquid crystal composition of the present invention using this composition as a basic constituent material was prepared, and a twisted nematic and super twisted nematic liquid crystal display device using the same was prepared. It was confirmed that this was an excellent one that did not generate any.

The nematic liquid crystal composition (2-2) is obtained by mixing the following base liquid crystal (b-1) with the general formula (I). Various characteristics of the base liquid crystal (b-1) were measured. The results were as follows.

[0064]

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T _NI : 54.5 ° C. T → _N : −40. ° C V _th : 1.60 V γ: 1.13 Δε: 6.7 Δn: 0.092 η: 21.0 c. p.

Comparing the characteristics, the liquid crystal composition of the present invention has a more preferable result because the birefringence is larger, the temperature range of the nematic phase is wider, and the ratio γ between the saturation voltage and the threshold voltage is smaller. Was. However, the general formula (I)
Has a greater viscosity and tends to increase the viscosity of the parent liquid crystal (b-1).

However, surprisingly useful facts have been found in spite of the above-mentioned viscous properties. That is, the response characteristics of the liquid crystal composition (2-2) of the present invention and the base liquid crystal (b-1) were measured and compared.
c, but 35.6 in the liquid crystal composition (2-2) of the present invention.
msec was a more favorable result.

From this, the compound of the general formula (I) is
Despite the greater viscosity, it has been found to have the effect of reducing the response speed. It is expected that such an effect has a peculiar tendency, for example, in the physical constant of the elastic constant or rotational viscosity of the compound of the general formula (I).

(Embodiment 3)

[0070]

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A nematic liquid crystal composition (2-3) was prepared, and various properties of the composition were measured. The results were as follows. T _NI : 96.1 ° C. T → _N : −70. ° C V _th : 1.89 V γ: 1.15 Δε: 8.9 Δn: 0.171

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. 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.

[0073]

The nematic liquid crystal composition of the present invention has a large birefringence Δn, exhibits a nematic phase over a wide temperature range, has an excellent effect of improving response characteristics, has a high voltage holding ratio, and has a high chemical stability. Is clearly higher.

Accordingly, the nematic liquid crystal composition of the present invention can be used for a twisted nematic or super twisted nematic liquid crystal display.

Further, it is possible to provide a liquid crystal display device which performs color display by the birefringence of the liquid crystal layer and the retardation plate. In particular, a large birefringence can reduce the thickness d of the liquid crystal layer, improve response characteristics, and provide display characteristics with a large amount of information.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C09K 19/34 C09K 19/34 G02F 1/13 500 G02F 1/13 500

Claims (19)

[Claims] 1. A liquid crystal composition comprising 5 to 40 compounds, wherein the liquid crystal composition has the general formula (I): (Wherein, R ¹¹ represents a linear alkyl group or alkoxy group having 1 to 10 carbon atoms, and X ¹¹ represents a linear alkyl group, alkoxy group, F, Cl or —CN having 1 to 10 carbon atoms.
Represents ), And a liquid crystal component A comprising one or more compounds represented by the following general formulas (II-1) to (II-4): (Wherein, R ^{21 to} R ²⁴ each independently represent 2 to 10 carbon atoms.
Linear alkyl group, alkenyl group or C _s H _{2s + 1} -O-
Represents C _t H _2t, s and t are each independently an integer of 1~5, Y ²¹ ~Y ²⁵ each independently represent a hydrogen atom or a fluorine atom, W ²¹ to ^W-23 each independently is represents a hydrogen atom or a fluorine atom, Z ²¹ represents a single bond, -COO- or -C ₂ H ₄ -
Wherein the hydrogen atom (H) of the cyclohexane ring in the general formula (II-1) may be substituted with a deuterium atom (D). A nematic liquid crystal composition comprising a liquid crystal component B consisting of one or more compounds selected from the group of compounds represented by (1). 2. The liquid crystal component A contains 30 to 100% by weight of a compound in which X ¹¹ in the general formula (I) is a fluorine atom.
The nematic liquid crystal composition according to claim 1, wherein the composition is contained. 3. The liquid crystal component A is a compound represented by the general formula (I), wherein R ¹¹ is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group, and / or X ¹¹ is a methyl group, 3. The nematic liquid crystal composition according to claim 1, wherein the composition contains 30 to 100% by weight of a compound represented by an ethyl group, a propyl group, a butyl group or a pentyl group. 4. The liquid crystal composition according to claim 1, wherein the liquid crystal component A is
The nematic liquid crystal composition according to any one of claims 1 to 3, wherein the composition comprises about 50% by weight. 5. The liquid crystal component B according to the general formula (II-1)
Wherein R ²¹ is an alkyl or alkenyl group having 2 to 5 carbon atoms, and / or Z ²¹
1 represented by the compounds - but a single bond, -COO- or -C ₂ H ₄
The composition according to claim 1, wherein the content is 0 to 100% by weight.
5. The nematic liquid crystal composition according to 2, 3, or 4. 6. The liquid crystal component B represented by the general formula (II-2)
Wherein R ²² is an alkyl group having 2 to 5 carbon atoms, and / or Y ²³ , Y ²⁴ , W ²¹ , W ²¹
A compound in which at least one of ²² is a fluorine atom
The composition according to claim 1, wherein the content is 0 to 100% by weight.
6. The nematic liquid crystal composition according to 2, 3, 4, or 5. 7. The liquid crystal component B represented by the general formula (II-3)
The compound of formula (1), wherein R ²³ is a compound represented by an alkyl group having 2 to 5 carbon atoms, and / or a compound wherein at least one of Y ²⁵ and W ²³ is represented by a fluorine atom, in an amount of 10 to 100% by weight. Claims 1, 2, 3, 4,
7. The nematic liquid crystal composition according to 5 or 6. 8. The liquid crystal component B represented by the general formula (II-4)
R in the compound of ^{twenty four}Is an alkyl group having 3 to 8 carbon atoms
Containing 10 to 100% by weight of the compound represented by
The method according to claim 1, 2, 3, 4, 5, 6, or 7,
Nematic liquid crystal composition. 9. The liquid crystal composition according to claim 1, wherein
9. The nematic liquid crystal composition according to claim 1, comprising 0 to 90% by weight. 10. The liquid crystal composition represented by the general formula (III-1)
~ (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,
Represents an alkoxy group, an alkenyl group, or an alkenyloxy group, Y ³¹ represents a hydrogen atom, a fluorine atom or —CH ₃ ;
³² and Y ³³ each independently represent a hydrogen atom or a fluorine atom, and Z ^{31 to} Z ³³ each independently represent a single bond, -COO- or-
Represents C ₂ H ₄ —, Z ³⁴ is a single bond, —C≡C— or —COO—
Wherein ring A ³¹ represents a cyclohexane ring or a cyclohexene ring, n ¹ and n ² each independently represent an integer of 0 or 1, and the hydrogen atom (H) of the cyclohexane ring in each compound is a deuterium atom (D ) May be substituted. )
The nematic liquid crystal composition according to any one of claims 1 to 9, further comprising a liquid crystal component C comprising one or more compounds represented by the following formulae. 11. The liquid crystal component C according to the general formula (III-
In the compound of 1), R ³¹ is a compound represented by a straight-chain alkyl group or alkenyl group having 2 to 5 carbon atoms, and / or R ³⁴ is a straight-chain alkyl group or alkoxy group having 1 to 5 carbon atoms. And / or a compound in which Z ³¹ is a single bond or —COO— is 10 to 100% by weight.
The nematic liquid crystal composition according to claim 10, which is contained. 12. The liquid crystal component C represented by the general formula (III-
In the compound of 2), R ³² is a compound represented by a linear alkyl group or alkenyl group having 2 to 5 carbon atoms, and / or R ³⁵ is a linear alkyl group or alkoxy having 1 to 5 carbon atoms. And / or a compound in which Z ³² is a single bond, —COO— or —C ₂ H ₄ —, and / or a compound in which ring A ³¹ is a cyclohexane ring.
The nematic liquid crystal composition according to claim 10, wherein the composition comprises 100% by weight. 13. The liquid crystal component C represented by the general formula (III-
In the compounds of 3), according to claim 10, 11 or 12 a nematic liquid crystal composition according to characterized in that it contains a compound Z ³⁴ is represented by -C≡C- 10 to 100 wt%. 14. The liquid crystal composition according to claim 1, wherein the liquid crystal component C contains at most 70% by weight.
14. The nematic liquid crystal composition according to 0, 11, 12 or 13. 15. The compound according to claim 1, wherein the liquid crystal composition is a compound having a core structure having four six-membered rings and having a liquid crystal phase-isotropic liquid phase transition temperature of 100 ° C. or higher.
The nematic liquid crystal composition according to any one of claims 1 to 14, wherein the composition comprises one or more kinds. 16. The liquid crystal composition has a dielectric anisotropy of 4 to 30, a birefringence of 0.08 to 0.33,
A nematic phase-isotropic liquid phase transition temperature of 70 ° C. or higher, and a crystal phase or smectic phase-nematic phase transition temperature of −10 ° C. or lower.
6. The nematic liquid crystal composition according to 5. 17. The nematic liquid crystal composition according to claim 1, wherein the liquid crystal composition contains a compound having an optically active group having an induced helical pitch of 0.5 to 1000 μm. 18. A twisted nematic or a super nematic using the nematic liquid crystal composition according to claim 17.
Twisted nematic liquid crystal display. 19. The liquid crystal display device according to claim 18, wherein the thickness of the liquid crystal layer is 1 to 30 μm.