JPH1036846A - Nematic liquid crystal composition and liquid crystal display made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nematic liquid crystal composition having a high birefringency, a wide drive temperature range and an excellent response, a liquid crystal display made by using the same and having improved electrooptical characteristics, and a light-scattering liquid crystal display which can realize uniform display and display characeristics and response characteristics stabilized against a temperature change. SOLUTION: This composition is a liquid crystal material containing a liquid crystal component comprising at least one compound represented by the formula (wherein R<11> is H or a 1-5C linear alkyl; R<12> is a 1-5C linear alkyl; and n is an integer of 2 or 4) and a liquid crystal component comprising at least two compounds having a Δε of +2 or above. The liquid crystal material has a Δεof 3 or above, a nematic-isotropic liquid phase transition temperature of 60 deg.C or above, and a crystalline- or smectic-nematicphase transition temperature of 0 deg.C or below.

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 K33 / K11 is 1.
Approximately 5, in addition to the dielectric anisotropy Δ △ and the relatively low viscosity, a material having a particularly large birefringence Δn is required. 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 a larger birefringence Δn is required because a material having a larger phase difference due to the difference in the wavelength of light is required, and a new liquid crystal compound or liquid crystal composition is still required. A proposal has been made.

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.) To cope with such display elements, new liquid crystal compounds or liquid crystal compositions such as those disclosed in No. 312949,
A proposal such as Japanese Patent Publication No. 5-501735 has been made.

A liquid crystal display device in which liquid crystal droplets are dispersed in a polymer is known as a bright and high-contrast liquid crystal device that does not require a polarizing plate or an alignment treatment. Tokushou Sho 58
Japanese Patent No. 501631 and U.S. Pat. No. 4,435,047 propose gelatin, gum arabic, polyvinyl alcohol and the like as encapsulating substances. It is known in, for example, JP-A-62-2231. These have a problem that the matching between the refractive index of the liquid crystal material and the refractive index of the polymer is optimized and a voltage as high as 25 V or more is required to obtain sufficient transparency.

US Pat. No. 5,304,323, and Japanese Patent Application Laid-Open No. 1-19872 disclose techniques for enabling low-voltage driving, high contrast, and time-sharing driving required for a liquid crystal display.
Japanese Patent Application Laid-Open No. 5 (1999) -2005 discloses a liquid crystal display device having a structure in which a liquid crystal material forms a continuous layer, and a polymer substance is distributed in a three-dimensional network in the continuous layer.

[0007] As a liquid crystal material for this purpose, for example, EP-A-359,146 discloses a method for optimizing the birefringence and dielectric anisotropy of a liquid crystal material.
No. 222320 discloses a technique for specifying the elastic constant of a liquid crystal material. Further, Japanese Patent Application Laid-Open No. 5-339573
And JP-A-6-123866 disclose a device having a contrast of about 40 in projection display by using a fluoro compound. However, required characteristics, high resistance value, excellent voltage holding ratio, low driving voltage, strong light scattering, high contrast ratio, fast response speed, good temperature characteristics, etc. There are problems in satisfying everything, and new proposals are still being made.

[0008]

In order to improve the above-described liquid crystal display characteristics, a liquid crystal material having a large birefringence Δn is required. Also, the higher chemical stability of the liquid crystal material,
A lower viscosity, a high-speed response of a liquid crystal display and a wider driving temperature range are also required.

For this purpose, for example, the following general formula (a)
-1)

[0010]

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(Wherein R and R 'represent an alkyl group or an alkoxy group). However, problems still remain. Specifically, it has specificity in compatibility with other liquid crystal materials, particularly compounds having strong polarity, and has a tendency that a smectic phase or a crystal phase is likely to appear. Further, the technology relating to the compound represented by the general formula (I) according to the present invention is described in, for example, JP-A-2-121936, but the knowledge of the physical properties and the mixture of the compound of the general formula (I) itself is disclosed. Has not yet been reported.

An object of the present invention is to solve or improve the above-mentioned problem. A nematic liquid crystal composition having a large birefringence Δn, a wide temperature range in which it can be driven, and excellent responsiveness. 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.

Also, in the above-mentioned light scattering type liquid crystal display, required display characteristics such as faster response, lower voltage drivability, higher resistance of the light control layer, and higher contrast ratio are maintained and improved. It is another object of the present invention to provide a light-scattering type liquid crystal display device in which a memory phenomenon, which will be described in detail later, is reduced, and more uniform display of white turbidity, improved display characteristics with respect to temperature change, and response characteristics are achieved. .

[0014]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems. General formula (I)

[0015]

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(Wherein R ¹¹ is a hydrogen atom or a group having 1 carbon atom)
Represents 5 to 5 linear alkyl groups, and R ¹² has 1 to 1 carbon atoms.
5 represents a linear alkyl group, and n represents an integer of 2 or 4. A) a liquid crystal component comprising at least one or more of the compounds represented by formula (I) and a liquid crystal component B comprising at least two or more compounds having a dielectric anisotropy Δ △ of at least +2; The liquid crystal material has a dielectric anisotropy Δ △ of 3 or more, a nematic phase-isotropic liquid phase transition temperature T _NI of 60 ° C. or more, and a crystal phase or a smectic phase-nematic phase transition temperature of 0 ° C. or less. A nematic liquid crystal composition, wherein T → _N. 2. 2. The nematic liquid crystal composition as described in 1 above, wherein in the general formula (I) of the liquid crystal component A, at least one compound in which R ¹¹ is a hydrogen atom is contained. 3. (1) wherein in the general formula (I) of the liquid crystal component A, n is 2 and at least one compound in which R ¹² is a methyl group or an ethyl group is contained.
The nematic liquid crystal composition according to the above. 4. In the liquid crystal material, the liquid crystal component A is 1 to 30.
4. The nematic liquid crystal composition according to the above 1, 2, or 3, wherein the composition contains 1% by weight. 5. The liquid crystal component B has a general formula (II-1) to (II-3)

[0017]

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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 H or F, Z ²¹ ~Z ²³ each independently represents a single _{bond, -COO -, - C 2 H} 4 - or -C ₄ H ₈ -
And Z ²¹ may also be —C≡C— or —CH ＝ CH—, Z ²⁴ and Z ²⁵ each independently represent a single bond, —COO— or —C≡C—, 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 the above 1, 2, 3, or 4, comprising at least two or more compounds selected from the second compound group consisting of the compounds represented by 6. In the compound wherein the liquid crystal component B is selected from the second compound group consisting of compounds represented by the general formulas (II-1) to (II-3), R ^{21 to} R ²³ each independently represent a number of carbon atoms. Two
7. The nematic liquid crystal composition according to the above item 5, comprising at least one compound represented by alkenyl group 7. 7. In the compound wherein the liquid crystal component B is selected from the second compound group consisting of compounds represented by the general formulas (II-1) to (II-3), X ^{21 to} X ²³ each independently represent F or Cl. , -O
7. The nematic liquid crystal composition according to the above item 5 or 6, comprising at least one compound represented by CF ₃ or —CN. 8. Wherein the liquid crystal material contains 10 to 99% by weight of a liquid crystal component B.
8. The nematic liquid crystal composition according to 5, 6 or 7. 9. 5. The liquid crystal display device according to item 5, wherein the liquid crystal component B contains 1 to 100% by weight of a compound selected from the second compound group consisting of compounds represented by formulas (II-1) to (II-3). 9. The nematic liquid crystal composition according to 6, 7 or 8. 10. In addition to the liquid crystal component, a liquid crystal component C represented by any of the general formulas (III-1) to (III-3)

[0019]

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(Wherein, R ^{31 to} R ³³ each independently represent a straight-chain alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^{34 to} R ³⁶ each independently represent 1 to 3 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 A ³² each independently represent a cyclohexane ring or a cyclohexene ring; i, j and k 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 above 1, 2, characterized in that it contains a compound selected from the third compound group consisting of the compound represented by
10. The nematic liquid crystal composition according to 3, 4, 5, 6, 7, 8, or 9. 11. 11. The nematic liquid crystal composition according to the above item 10, wherein the liquid crystal material contains at most 75% by weight of the liquid crystal component C. A dielectric anisotropy Δε of 12.4 to 25, a nematic phase-isotropic liquid phase transition temperature T _NI of 70 ° C. or more,
Wherein the crystalline phase or smectic phase-nematic phase transition temperature T → _N of −10 ° C. or lower is T → _N.
2. The nematic liquid crystal composition according to 1. 13. 13. The nematic liquid crystal composition according to any one of the above items 1 to 12, wherein the birefringence Δn is in the range of 0.16 to 0.30. 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. 14. A twisted nematic or super twisted nematic liquid crystal display using the nematic liquid crystal composition according to any one of the above 1 to 13. 16. 16. The liquid crystal display device according to the above item 14 or 15, wherein the thickness of the liquid crystal layer is 1 to 10 μm. 17． 14. A light-scattering type liquid crystal display device having a dimming layer containing the liquid crystal material and the transparent solid substance according to 1 to 13. 18. 18. The light-scattering type liquid crystal display device according to the above item 17, wherein the liquid crystal material forms a continuous layer, and the transparent solid substance is a light control layer in which a uniform three-dimensional network structure is formed in the continuous layer. . 19. 19. The light-scattering type liquid crystal display device according to the above item 17 or 18, wherein the transparent solid substance is formed from a polymerizable composition containing a polymer-forming bifunctional monomer and a monofunctional monomer. Was found as a means for solving the above-mentioned problem.

[0021]

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 lower viscosity, a higher birefringence Δn, a higher 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, as the liquid crystal component A, as a preferred embodiment, in the compound represented by the general formula (I), R ¹¹ is a hydrogen atom, and / or n is an integer of 2 or 4; It is preferable that R ¹² has at least one carbon atom.
Alternatively, 3 linear alkyl groups are preferred, and 1 is particularly preferred.

More specifically, general formulas (I-1) to (I-3)

[0024]

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(Wherein, R ¹² has the same meaning as in formula (I)).

The liquid crystal composition of the present invention containing a liquid crystal component A comprising at least one or two or more compounds represented by the general formula (I) comprises a TN-LC
D. To make liquid crystal display devices such as STN-LCD, TFT-LCD and the like more improved electro-optical characteristics, and particularly to make the response at low temperature and the temperature dependency of the steepness drive voltage more preferable.

The liquid crystal component A is one of the compounds of the general formula (I)
Although it is a kind or two or more kinds, even if it is one kind, the above effects can be obtained. The liquid crystal component A can be contained in the range of 1 to 30% by weight, preferably 5 to 25% by weight, and more preferably 5 to 2% by weight based on the liquid crystal composition of the present invention.
A range of 0% by weight is more preferred.

The liquid crystal composition of the present invention contains, in addition to the above liquid crystal component A, a liquid crystal component B comprising 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, -OC
N, -NCS, -F, -Cl, -NO 2, -CF 3, -OCF 3, -
It is a compound that is OCHF _2. 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.

It is necessary that the liquid crystal component B comprises at least two or more compounds having a dielectric anisotropy of +2 or more, but preferably 3 to 15 types. A compound having a dielectric anisotropy of +8 to +13, a compound having a dielectric anisotropy of +14 to +18,
It is preferable to appropriately select and contain from compounds of +18 or more, and it is possible to obtain predetermined drive voltage and response characteristics. In this case, it is preferable to mix compounds having a dielectric anisotropy of +8 to +13 in a range of at most 10 or less,
The compounds of +14 to +18 are preferably mixed in a range of at most 8 or less, and the compounds of +18 or more are preferably mixed in a range of at most 10 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 can be contained in the liquid crystal composition of the present invention in a range of 10 to 99% by weight, and more preferably in a range of 25 to 70% by weight.

The crystalline 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, 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, more preferably 80 ° C. to 130 ° C., and a dielectric anisotropy of 3 or higher is required. Is preferably in the range of 4 to 40.
A range of 25 is more preferable, a range of 4 to 16 when high-speed response is emphasized, and a range of 17 to 25 when a lower drive voltage is required. The birefringence △ n
Requires 0.10 or more, and particularly preferably 0.16 to 0.30. The properties of such a nematic liquid crystal composition are as follows: active matrix type, twisted nematic or super twisted type.
Useful for nematic liquid crystal display devices.

The above nematic liquid crystal composition is useful for TN-LCDs and STN-LCDs having a high response speed, and can provide a 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 a general formula (II-
1) Two or more compounds selected from the second compound group represented by (II-3) can be contained, and the second compound group can be contained in the range of 1 to 100% by weight. ,
A range of 50 to 100% by weight is preferred. General formula (II-1)
As a more preferred form in the second compound group represented by-(II-3), R ²¹ -R ²³ are each independently represented by an alkenyl group having 2 to 7 carbon atoms, and / or X ^21- X ²³
But F, Cl, -OCF _3, or nematic liquid crystal composition comprising at least one or more selected compounds represented by -CN are preferred.

More specifically, general formulas (II-4) to (II-2)
It is a compound represented by 1). The dielectric anisotropy of these compounds is +2 or more.

[0034]

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[0035]

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[0036]

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(Wherein, R ^{21 to} R ²³ , X ^{21 to} X ²³ , Y ²¹ to
Y ²⁹ has the same meaning as in formulas (II-1) to (II-3). )

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

More specifically, R ²¹ is preferably an alkyl or alkenyl group having 2 to 5 carbon atoms, and particularly preferably contains at least one compound having an alkenyl group. R ²² is preferably a compound of an alkyl group, alkenyl group or alkoxy group having 2 to 5 carbon atoms. It is preferable to frequently use a compound in which X ^{21 to} X ²³ are each independently F, Cl, —OCF ₃ , or —CN. When emphasis is placed on high-speed response, X ^{21 to} X ²³ are each independently F or —. It is preferable to use a large amount of the compound which is OCF ₃ , and when a higher birefringence is required, X
It is preferable to frequently use a compound in which ^{21 to} X ²³ are each independently Cl, —OCF ₃ , or —CN. When a lower driving voltage is required, X ^{21 to} X ²³ are each independently Cl, —CN. It is preferable to frequently use a compound of the formula:

Also, an active matrix display system,
Super-TFT combined with TFT-LCD, MIM-LCD, IPS mode and light-scattering type liquid crystal display device with active matrix technology (for example, display device having a dimming layer containing liquid crystal material and transparent solid substance) the, X ²¹ ~X ²³
It is preferable to frequently use a compound wherein is -F. Y ²¹ ~
Y ²⁹ is preferably the case of emphasizing high-speed responsiveness is intensive compound is H, when improving the temperature dependency of the driving voltage, compound Y ²¹ to Y ²⁹ is F, particularly preferably Y ²¹ , Y ²³ , Y ^{25 to} Y ²⁷ , and Y ²⁹ are preferably F. When Y ²⁵ and Y ²⁶ are F, Y ²⁴ is preferably used.
Can be further improved by selecting a compound in which Y is H. In the case of the general formula (II-3), selecting a compound in which Y ²⁹ is F can further improve the compatibility. Z ^{21 to} Z ²³ each independently represent a single bond, —COO—, —C ₂ H ₄ —, or —C ₄ H ₈ —, and one of Z ²¹ and Z ²² is a single bond. Compounds are preferable, and in order to improve the responsiveness and compatibility at low temperatures, it is preferable to use a single bond compound and a compound of —C ₂ H ₄ — in combination. Z ²⁴ and Z ²⁵ are a single bond, —COO
-, -C≡C-, and when the birefringence Δn needs to be larger, it is preferable to use a compound of -C≡C- frequently. l and m each independently represent 0 or 1, and the compounds of formulas (II-1) and (II-2) wherein l and m are 0, and compounds represented by formulas (II-1) and (II-2) )), The mixing ratio of the compound having l and m of 1 and the compound of the general formula (II-3) is 0.
~ 100 to 100 ~ 0
If a higher T _NI is required, the general formulas (II-1), (I
A compound in which l and m in I-2) are 1 and a compound of the general formula (II-3)
It is preferable to frequently use the compound of formula (1). General formula (II-1),
A compound in which the hydrogen atom (H) in the cyclohexane ring of (II-2) is replaced by a deuterium atom (D) can be used, and this compound is suitable for adjusting the elastic constant of the liquid crystal composition and for aligning the film. Is useful for adjusting the pretilt angle
It is preferable to include at least one compound substituted with a deuterium atom (D).

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.

[0042]

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[0043]

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(In the formula, R ^{31 to} R ³⁶ and Y ^{32 to} Y ³⁴ have the same meanings as in the general formulas (III-1) to (III-3).)

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.

In addition, the present inventors have found that since the liquid crystal composition has a large birefringence, at least one of the liquid crystal compositions having a transparent electrode layer has a dimming layer sandwiched between two transparent substrates. However, they have found that the light modulating layer is also useful for providing a light-scattering type liquid crystal display containing a liquid crystal material and a transparent solid substance to provide high contrast due to advantageous light scattering characteristics.

A liquid crystal material having a large birefringence is usually
Often, an induced crystalline phase or a partially crystallized smectic phase develops, conversely, the liquid crystal phase becomes narrower, or exhibits a liquid crystal phase with a large birefringence and a wide temperature. It has not been possible to achieve a particularly high voltage holding ratio, which is essential for the method. Furthermore, when a light-scattering type liquid crystal display is manufactured, the light transmittance T ₀ when no voltage is applied is switched from the voltage applied state to the non-applied state compared to the value immediately after fabrication or the value left for a long time after voltage application. A memory phenomenon occurs in which the value immediately after is increased, and as a result, the contrast of the liquid crystal display is deteriorated. If a fluorotoluene-based compound is simply used, the desired result is not necessarily obtained. is there. The liquid crystal composition of the present invention avoids or reduces such a problem.

It has also been found that the liquid crystal composition of the present invention is a liquid crystal material that exhibits high compatibility with a polymer-forming compound that forms a transparent solid substance. The transparent solid substance is preferably formed by polymerizing a polymer-forming compound, for example, a light control layer obtained by mixing a UV-curable resin composition containing a compound having a UV-curable vinyl group with a liquid crystal material. After sandwiching the forming material between two substrates, the ultraviolet-curable resin composition is cured to produce the resin composition. When the compatibility between the polymer-forming compound and the liquid crystal material is higher, it is possible to obtain a more uniform solution in a wider temperature range. Then, when the polymer-forming compound is cured in such a state, a light control layer having light scattering properties can be produced with no or little deviation, and there is no unevenness in driving voltage and contrast ratio. It is possible to provide a light-scattering type liquid crystal display that achieves display characteristics and achieves more uniform display of white turbidity. Therefore, a liquid crystal material suitable for producing a liquid crystal display exhibiting more uniform light scattering characteristics or a relatively large liquid crystal display by using a vacuum injection method or the like has been found.

As the liquid crystal material, a liquid crystal compound having no cyano group is preferably used in order to obtain a high voltage holding ratio or a large birefringence of 0.200 or more required in the active matrix system. As the liquid crystal compound to be used, a tolan compound represented by the general formula (I) is preferable, and it is preferable to combine with a fluorotolan compound represented by the general formula (II-2) or (II-3). 3
More preferably, a fluorotolan compound having two rings is used as an essential component. By containing the tolan compound represented by the general formula (I), it is possible to provide a light-scattering liquid crystal display device which has an effect of improving responsiveness and is useful for displaying moving images. Also, to prepare a liquid crystal display having a higher voltage holding ratio, it is preferable to use a higher specific resistance liquid crystal material, the specific resistance 10 ¹¹
It is preferably Ω · cm or more, more preferably 10 ¹² Ω · cm or more, and most preferably 10 ¹³ Ω · cm or more.

The present inventors have disclosed in Japanese Patent Application Laid-Open No. Hei 6-222320 that the relationship between the physical properties of a liquid crystal material and the display characteristics of a liquid crystal display is represented by the following equation (IV).

[0051]

(Equation 1)

V _th represents a threshold voltage,
¹ K _ii , ² K _ii represent elastic constants, i represents 1, 2 or 3, Δε represents dielectric anisotropy, <r> represents an average gap distance at a transparent solid material interface, A represents the anchoring energy of the transparent solid substance with respect to the liquid crystal molecules, and d represents the distance between the substrates having the transparent electrodes.

This equation means that the regulating force exerted on the liquid crystal molecules by the transparent solid interface changes depending on the ratio between the elastic constant K _ii and the anchoring energy A. In particular, the effect is smaller than the actual average air gap <r>, which substantially increases the amount of K _ii / A, thereby effectively reducing the driving voltage. This relationship can also be applied to the present invention, and by selecting the dielectric anisotropy Δε and the elastic constant of the liquid crystal material according to the liquid crystal compound constituting the liquid crystal material, a more preferable liquid crystal display driven at a low voltage is obtained. What you can get. More specifically, the following is preferable.

By forming the transparent solid substance from a polymerizable composition containing a bifunctional monomer and a monofunctional monomer as a polymer-forming compound, more excellent display characteristics of liquid crystal display can be obtained. By using a composition in which a bifunctional monomer and a monofunctional monomer are combined as the polymer-forming compound, the shape of the transparent solid material becomes more uniform in the process of forming the transparent solid material from the polymer-forming compound. It is thought that the structure of the liquid crystal material can be controlled and the properties of the interface with the liquid crystal material can be manipulated. More specifically, the average air gap <r> and the anchoring energy A in Equation (IV) can be made superior. In this way,
The drive voltage can be reduced while maintaining cloudiness and transparency. Further, for example, a liquid crystal material containing the compound represented by the general formula (I) described above can be obtained by using a polymerizable composition in which a bifunctional monomer and a monofunctional monomer are used in combination as a polymer-forming compound. In addition, the memory phenomenon can be eliminated or reduced.

The liquid crystal material used in the present invention is a light scattering type liquid crystal display device in which liquid crystal droplets obtained by microencapsulating a liquid crystal material between two substrates having a transparent electrode layer are dispersed in a transparent solid substance. It is also expected to be useful. The transparent solid substance formed between the substrates may be in the form of a fiber or a particle, or may be in the form of a film in which a liquid crystal material is dispersed in the form of droplets, but has a uniform three-dimensional network structure. Are more preferred. Further, the liquid crystal material preferably forms a continuous layer, but is important for forming an optical boundary surface by forming a disordered state of the liquid crystal material and for exhibiting light scattering. The average diameter of the shape of the three-dimensional network structure formed from such a transparent solid material is too large or too small compared to the wavelength of light. ~ 2
The range of μm is preferred. Further, the thickness of the light control layer is preferably in the range of 2 to 30 μm, and
The range of m is particularly preferred.

In the liquid crystal display of the present invention thus manufactured, the present inventors have conducted intensive studies on the liquid crystal material and the transparent solid substance constituting the liquid crystal display utilizing the light scattering opaque state and the transparent state. The liquid crystal compound constituting the material, compatibility with the polymer-forming compound and finding a preferable configuration of the polymerizable composition, faster response, lower voltage drivability, higher light control layer resistance, Alternatively, while maintaining and improving display characteristics such as a higher contrast ratio, the memory phenomenon is reduced, and a more uniform display of white turbidity is achieved, thereby having characteristics required for an active matrix system. The liquid crystal display of the present invention can be used, for example, as a projection display device or a direct-view portable terminal display (Personal Digital Assistance).

[0057]

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 represents “% 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 constructing a TN-LCD having a cell thickness of 6 μm Γ: ratio of saturation voltage (V _sat ) to V _th Δε: dielectric anisotropy Δn: birefringence η: viscosity at 20 ° C. (cp)

(Example 1)

[0061]

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The 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: 100.7 ℃ T → N} : -50. ° C _Vth : 1.98 V Δε: 8.1 Δn: 0.165 η: 17.7 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 2)

[0065]

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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 : 104.3 ° C. T → _N : −30. ° C _Vth : 2.20 V γ: 1.12 Δε: 7.5 Δn: 0.211

When a TN-LCD having a cell thickness d of 2.4 μm was constructed and its display characteristics were measured, a liquid crystal display device having a threshold voltage of 1.92 V and a response speed of 0.7 msec was obtained. Was done.

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. The change in threshold voltage in the temperature range from 70 ° C. to −40 ° C. was measured to be 1.9.
mV / ° C., the display characteristics were stable over a wide temperature range. Therefore, it can be understood that this liquid crystal composition is useful for high time division driving.

(Embodiment 3)

[0070]

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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 : 70.7 ° C. T → _N : −70. ° C _Vth : 1.69 V Δε: 9.8 Δn: 0.219 η: 21.4 c. p.

(Embodiment 4)

[0073]

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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 : 80.0 ° C. T → _N : −40. ° C _Vth : 1.45 V Δε: 12.6 Δn: 0.209 η: 34.0 c. p.

(Comparative Example 1)

[0076]

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A comparative liquid crystal composition (a-2) was prepared, and various characteristics of the composition were measured. The results were as follows. T _NI : 76.1 ° C. T → _N : −13. ° C _Vth : 1.47 V Δε: 12.3 Δn: 0.202 η: 36.4 c. p.

The difference from Example 4 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 temperature range of the nematic phase was wider, the birefringence was larger, and the viscosity was more preferable.

(Embodiment 5)

[0080]

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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. _TNI : 95.4 ° C T → _N : −30. ° C _Vth : 1.79 V γ: 1.12 Δε: 11.5 Δn: 0.242

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.

When a TN-LCD having a cell thickness d of 2.1 μm was constructed and its display characteristics were measured, a liquid crystal display device having a threshold voltage of 1.61 V and a response speed of 0.5 msec was obtained. Was done.

(Embodiment 6)

[0085]

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A nematic liquid crystal composition No. 3-
6 were prepared, and various properties of the composition were measured. The results were as follows. T _NI : 92.6 ° C. T → _N : −40. ° C _Vth : 2.02 V γ: 1.12 Δε: 7.3 Δn: 0.202 η: 25.1c. p. Voltage holding ratio before test: 99.1% Voltage holding ratio after heating acceleration test: 97.6%

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 a TN-LCD having a cell thickness d of 2.1 μm was constructed and its display characteristics were measured, a liquid crystal display device having a threshold voltage of 1.61 V and a response speed of 0.5 msec was obtained. Was done.

The nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, and 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 7)

[0091]

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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 : 96.7 ° C. T → _N : −35. ° C _Vth : 2.28 V Δε: 6.3 Δn: 0.274 Voltage holding ratio before test: 99.2% Voltage holding ratio after heating acceleration test: 98.3%

The nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, and 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 8)

[0095]

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A nematic liquid crystal composition No. 3-
8 and the properties of this composition were measured. The results were as follows. T _NI : 104.3 ° C. T → _N : −70. ° C. V _th : 1.91 V Δε: 8.0 Δn: 0.147 η: 20.1 c. p. Voltage holding ratio before test: 99.3% Voltage holding ratio after heating acceleration test: 98.4%

The nematic liquid crystal composition has a high voltage holding ratio after the heating acceleration test, and 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.

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. 70 ° C to -30 ° C
The change of the drive voltage in the temperature range of was measured.
As small as 2 mV / ° C., stable display characteristics were exhibited 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.

(Embodiment 9) 3-2-No. 3-7
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 This is useful for a liquid crystal display system.

Hereinafter, the light scattering type liquid crystal display will be described in more detail. However, the invention is not limited to these examples. In addition, each of the evaluation characteristics in the following examples means the following symbols and contents. V ₉₀ , V ₁₀ : light transmittance of the device when no voltage is applied (T ₀ )
Is 0%, and when the transmittance (T ₁₀₀ ) when the light transmittance does not change with the increase of the applied voltage is 100%,
The applied voltage (V) at which the light transmittance is 90% is V ₉₀ , and the applied voltage at which the light transmittance is 10% is V ₁₀ . Contrast: With the device removed from the photometry, the light transmittance when the light source is turned on is set to 100%, the light transmittance when the light source is turned off is set to 0%, and the light transmittance of the device when no voltage is applied is T.
₀ , where T ₁₀₀ is the value represented by T ₁₀₀ / T _0, where T ₁₀₀ is the light transmittance saturated with an increase in the applied voltage. The measurement was performed using an optical device having a condensing angle of 6 °. Retention: After a device was aged at a temperature of 150 ° C. for 1 hour, a rectangular wave having a temperature of 80 ° C., a frame frequency of 60 Hz, a peak voltage of V90, and an ON state of 67 μs was applied, and the charge accumulated in the ON state was Q. ₀ , the current leaking in the OFF state is measured by a high impedance voltmeter, and when the remaining charge is Q, it is a value represented by (Q / Q ₀ ) × 100. T _MLC : a temperature at which a liquid crystal material and a polymer-forming compound are mixed at a temperature necessary to form a homogeneous solution, and at which a transition temperature from an isotropic liquid to a nematic phase upon cooling or a temperature at which phase separation occurs.

Example 10 As a liquid crystal material, a liquid crystal composition No. 80% of 3-5 and "H" as a polymer-forming compound
X-220 "(manufactured by Nippon Kayaku Co., Ltd.) 13.86%, lauryl acrylate 5.94%, and 2-hydroxy-2-methyl-1-phenylpropan-1-one as a polymerization initiator 0.2% To form a light modulating layer forming material in a uniform solution. The T _MLC of this dimming layer forming material is about 40 ° C.
Met. This light modulating layer forming material is placed in an empty cell of 50 × 50 mm produced by using two ITO electrode glass substrates interposed with spacers having an average particle diameter of 10 μm, 10 ° C. higher than the transition temperature T _MLC of the uniform solution. Vacuum was injected under temperature. While maintaining this at a temperature 3 ° C. higher than the transition temperature T _MLC of the homogeneous solution, a metal halide lamp (80 W / cm
² ) pass under 3.5 m / min at a speed of 3.5 m / min.
The polymer-forming compound was cured by irradiating ultraviolet rays having an energy corresponding to cm ² to obtain a liquid crystal device having a dimming layer composed of a liquid crystal material and a transparent solid substance. When the cross section of the cured product formed between the substrates of the obtained liquid crystal device was observed using a scanning electron microscope, a transparent solid substance having a three-dimensional network structure composed of a polymer was recognized. The characteristics of the obtained light scattering type liquid crystal display showed uniform display characteristics without unevenness, and the various characteristics were as follows.

[0102] _{V 10: 4.6 V V 90:} 7.4 V T 0: 1.8% T 100: 88.4% Contrast: 1:49

The above liquid crystal device maintains the above characteristics at a temperature of 0 to 50 ° C. and is useful for temperature characteristics. The hysteresis peculiar to this kind is as small as 0.1 V or less, and the response speed at 0 ° C. is 300 msec. The following were improved. Such a characteristic, compared with the conventional light scattering type liquid crystal device,
It shows a wide operating temperature range, is capable of driving at 1/2 to 1/8 duty, and achieves uniform and uniform display characteristics, and can be used for decorative display boards such as advertising boards, display devices such as clocks, or reflectors. It was useful for a direct-view display device or the like having the same.

(Example 11) In Example 10, the liquid crystal composition No. In place of liquid crystal composition No. 3-5, 3-7
A liquid crystal device having a light modulating layer composed of a liquid crystal material and a transparent solid substance was obtained in the same manner as in Example 10, except for using. Various characteristics of the obtained liquid crystal device were as follows.

Characteristics of liquid crystal device: V ₁₀ : 5.2 V V ₉₀ : 9.0 V T ₀ : 1.0% T ₁₀₀ : 88.9% Contrast: 1:89 Retention: 98.5%

The liquid crystal device maintains the above characteristics at a temperature of 0 to 60 ° C. and is useful for temperature characteristics. The hysteresis specific to this type is as small as 0.1 V or less, and the response speed at 40 ° C. is about It was improved to 30 msec. Such characteristics, compared to the conventional light scattering type liquid crystal device, show a wider operating temperature range, have a favorable response to moving images, and achieve a uniform and even display characteristics, such as advertising boards It is useful for a display device such as a decorative display plate or a clock, or a projection display device.

[0107]

The nematic liquid crystal composition of the present invention has a large birefringence Δn, exhibits a nematic phase over a wide temperature range, and has a high voltage holding ratio and high chemical stability. Therefore, the nematic liquid crystal composition of the present invention can be used for an active matrix type, twisted nematic or super twisted nematic liquid crystal display device.

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. Furthermore, a useful device can be provided for a light scattering type liquid crystal display having a light control layer containing a liquid crystal material and a transparent solid substance.

Claims (19)

[Claims] 1. A compound of the general formula (I) (Wherein, R ¹¹ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, R ¹² represents a linear alkyl group having 1 to 5 carbon atoms, and n is an integer of 2 or 4) A liquid crystal material comprising a liquid crystal component A consisting of at least one kind or two or more kinds of compounds represented by formula (I) and a liquid crystal component B consisting of at least two kinds of compounds having a dielectric anisotropy Δ △ of +2 or more. The liquid crystal material has a dielectric anisotropy Δ △ of 3 or more, a nematic phase of 60 ° C. or more—an isotropic liquid phase transition temperature T _NI , and a crystal phase or a smectic phase of 0 ° C. or less—
A nematic liquid crystal composition characterized by having a nematic phase transition temperature T → _N. 2. The nematic liquid crystal composition according to claim 1, wherein in the general formula (I) of the liquid crystal component A, at least one compound in which R ¹¹ is a hydrogen atom is contained. 3. A general formula of the liquid crystal component A in (I), n is 2, claim 1, R ^{1 2} is characterized in that it contains at least one kind of the compound is a methyl group or an ethyl group Or the nematic liquid crystal composition according to 2. 4. In the liquid crystal material, the liquid crystal component A
1 to 30% by weight.
4. The nematic liquid crystal composition according to 2 or 3. 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 , —CF ₃ or —CN, Y ^{21 to} Y ²⁹ each independently represent H or F, Z ^{21 to} Z ²³ each independently represent a single bond, —COO—, —C ₂ H ₄ — Or —C ₄ H ₈ —, Z ²¹ may also be —C≡C— or —CH ＝ CH—, Z ²⁴ , Z
²⁵ independently represents a single bond, -COO- or -C≡C-; l and m each independently represent 0 or 1; and the hydrogen atom (H) of the cyclohexane ring in each compound is a deuterium atom. (D) may be substituted. 4. The method according to claim 1, wherein at least two kinds of compounds selected from the second compound group consisting of compounds represented by the formula (1) are contained.
Or the nematic liquid crystal composition according to 4. 6. The liquid crystal component B represented by the following general formula (II-1):
In a compound selected from the second compound group consisting of compounds represented by (II-3), at least one compound in which R ^{21 to} R ²³ are each independently represented by an alkenyl group having 2 to 7 carbon atoms. 6. The nematic liquid crystal composition according to claim 5, comprising at least one kind. 7. The liquid crystal component B represented by the general formula (II-1):
In a compound selected from the second compound group consisting of the compound represented by (II-3), a compound in which X ^{21 to} X ²³ are each independently represented by F, Cl, —OCF ₃ , or —CN The nematic liquid crystal composition according to claim 5, wherein the composition comprises at least one kind. 8. The liquid crystal material, wherein a liquid crystal component B is 1
The composition according to claim 1, which is contained in an amount of 0 to 99% by weight.
8. The nematic liquid crystal composition according to 2, 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, wherein the composition comprises 1 to 100% by weight of a compound selected from the second compound group consisting of the compound represented by (II-3). 10. In addition to the liquid crystal component, a liquid crystal component C may be represented by one of the general formulas (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—, and rings A ³¹ and A ³² each independently represent a cyclohexane ring or a cyclohexene ring; j and k each independently represent an integer of 0 or 1,
The hydrogen atom (H) of the cyclohexane ring in each compound may be substituted with a deuterium atom (D). ), A compound selected from the third compound group consisting of compounds represented by the following formulas:
10. The nematic liquid crystal composition according to 6, 7, 8 or 9. 11. The nematic liquid crystal composition according to claim 10, wherein the liquid crystal material contains at most 75% by weight of the liquid crystal component C. 12. A dielectric anisotropy Δ △ of 4 to 25,
Nematic phase-isotropic liquid phase transition temperature T above 70 ° C
The nematic liquid crystal composition according to any one of claims 1 to 11, wherein the composition is _NI and has a crystal phase of -10 ° C or less or a smectic phase-nematic phase transition temperature T → _N. 13. The nematic liquid crystal composition according to claim 1, wherein the birefringence Δn is in the range of 0.16 to 0.30. 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. 16. The liquid crystal display device according to claim 14, wherein the thickness of the liquid crystal layer is 1 to 10 μm. 17. A light-scattering type liquid crystal display device having a dimming layer containing the liquid crystal material according to claim 1 and a transparent solid substance. 18. The light control layer according to claim 17, wherein the liquid crystal material forms a continuous layer, and the transparent solid substance forms a uniform three-dimensional network structure in the continuous layer. Light scattering type liquid crystal display device. 19. Light scattering according to claim 17, wherein the transparent solid substance is formed from a polymerizable composition containing a polymer-forming bifunctional monomer and a monofunctional monomer. Liquid crystal display device.