CN115678570A

CN115678570A - Liquid crystal composition, use thereof, and liquid crystal display element

Info

Publication number: CN115678570A
Application number: CN202210579987.1A
Authority: CN
Inventors: 松尾美保; 伊是名省吾; 木村敬二
Original assignee: JNC Corp; JNC Petrochemical Corp
Current assignee: JNC Corp; JNC Petrochemical Corp
Priority date: 2021-07-27
Filing date: 2022-05-26
Publication date: 2023-02-03
Also published as: KR20230017123A; TW202307180A

Abstract

The invention provides a liquid crystal composition which fully satisfies at least one of the characteristics of high upper limit temperature of a nematic phase, low lower limit temperature of the nematic phase, low viscosity, appropriate optical anisotropy, high dielectric anisotropy, high elastic constant, low ratio of rotational viscosity to elastic constant, high dielectric constant in a short axis direction, and high ratio of dielectric constant in the short axis direction to dielectric anisotropy, and a use and a liquid crystal display element thereof. A liquid crystal composition containing a specific compound having a large elastic constant and a large dielectric constant in the short axis direction as component A and a specific compound having a large dielectric anisotropy as component B, and may also contain a specific compound having a small viscosity or a high upper limit temperature as component C and a specific compound having a large dielectric constant in the short axis direction as component D.

Description

Liquid crystal composition, use thereof, and liquid crystal display element

Technical Field

The present invention relates to a liquid crystal composition, a liquid crystal display element containing the same, and the like. In particular, the present invention relates to a liquid crystal composition having positive dielectric anisotropy, and an Active Matrix (AM) device having Twisted Nematic (TN), electrically Controlled Birefringence (ECB), optically Compensated Bend (OCB), in-plane switching (IPS), fringe Field Switching (FFS), or field-induced photo-reactive alignment (FPA) modes, which includes the composition.

Background

In a liquid crystal display device, the operation modes based on liquid crystal molecules are classified into Phase Change (PC), twisted Nematic (TN), super Twisted Nematic (STN), electrically Controlled Birefringence (ECB), optically Compensated Bend (OCB), in-plane switching (IPS), vertical Alignment (VA), fringe Field Switching (FFS), field-induced photo-reactive alignment (FPA), and the like. The driving methods of the elements are classified into Passive Matrix (PM) and Active Matrix (AM). The PM is classified into a static type (static), a multiplexing type (multiplex), etc., and the AM is classified into a Thin Film Transistor (TFT), a Metal Insulator Metal (MIM), etc. TFTs are classified into amorphous silicon (amorphous silicon) and polycrystalline silicon (polycrystalline silicon). The latter is classified into a high temperature type and a low temperature type according to the manufacturing process. The light source is classified into a reflection type using natural light, a transmission type using a backlight, and a semi-transmission type using both natural light and backlight.

The liquid crystal display element contains a liquid crystal composition having a nematic phase. The composition has suitable properties. By improving the characteristics of the composition, an AM element having good characteristics can be obtained. The correlation between these properties is summarized in table 1 below. The properties of the composition are further illustrated based on commercially available AM elements. The temperature range of the nematic phase is associated with the temperature range in which the element can be used. The upper limit temperature of the nematic phase is preferably about 70 ℃ or higher, and the lower limit temperature of the nematic phase is preferably about-10 ℃ or lower. The viscosity of the composition correlates to the response time of the element. In order to display a moving image with the element, the response time is preferably short. Ideally shorter than 1 millisecond of response time. Therefore, it is preferable that the viscosity of the composition is small. Further, it is preferable that the viscosity at low temperature is low. The elastic constant of the composition correlates to the contrast of the element. In the element, the elastic constant of the composition is preferably large in order to improve the contrast. The ratio of the rotational viscosity of the composition relative to the elastic constant (e.g., γ 1/K22) is correlated to a parameter of the response time of the element. In the element, the ratio is preferably small in order to shorten the response time.

TABLE 1 Properties of the compositions and AM elements

The optical anisotropy of the composition correlates with the contrast of the element. Depending on the mode of the element, a large optical anisotropy or a small optical anisotropy, that is, an appropriate optical anisotropy is required. The product (Δ n × d) of the optical anisotropy (Δ n) of the composition and the cell gap (d) of the element is designed to maximize the contrast. The value of the appropriate product depends on the kind of the operation mode. In a TN-type element or the like, a suitable value is about 0.45. Mu.m. In this case, a composition having a large optical anisotropy is preferable for an element having a small cell gap. The large dielectric anisotropy of the composition contributes to a low threshold voltage, small power consumption, and large contrast of the device. Therefore, a large dielectric anisotropy is preferable. The large specific resistance of the composition contributes to a large voltage holding ratio and a large contrast ratio of the element. Therefore, a composition having a large specific resistance in the initial stage is preferable. Preferred are compositions having a large specific resistance after long-term use. The stability of the composition to ultraviolet rays and heat correlates with the lifetime of the liquid crystal display element. At high stability, the lifetime of the element is long. Such characteristics are preferable for AM elements used for liquid crystal monitors, liquid crystal televisions, and the like.

A composition having positive dielectric anisotropy is used for an AM element having a TN mode. A composition having negative dielectric anisotropy is used for an AM element having a VA mode. A composition having positive or negative dielectric anisotropy is used for an AM element of an IPS mode or an FFS mode. A composition having positive or negative dielectric anisotropy is used in an AM element of a Polymer Sustained Alignment (PSA) type.

Patent documents 1 to 3 disclose a compound having a phenanthrene structure and a liquid crystal composition containing the compound and having negative dielectric anisotropy. Patent document 4 discloses a liquid crystal composition containing a compound having positive dielectric anisotropy and a compound having negative dielectric anisotropy.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. Hei 8-53672

[ patent document 2] International publication No. 2002-051963

[ patent document 3] Japanese patent laid-open No. 2006-206888

[ patent document 4] International publication No. 2014-045905

Disclosure of Invention

[ problems to be solved by the invention ]

The problem of the present invention is to provide a liquid crystal composition, the polymer fully satisfies at least one of characteristics such as a high upper limit temperature of a nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a high dielectric anisotropy, a high elastic constant, a low ratio (gamma 1/K22) of rotational viscosity to elastic constant, a high dielectric constant (epsilon) in the short axis direction, a high ratio (epsilon/delta epsilon) of the dielectric constant to dielectric anisotropy in the short axis direction, a high specific resistance, a high stability to light, and a high stability to heat. Another problem is to provide a liquid crystal composition having an appropriate balance between at least two of these characteristics. Another problem is to provide a liquid crystal display element containing such a composition. Still another problem is to provide an AM device having characteristics such as a short response time, a high voltage holding ratio, a low threshold voltage, a high contrast ratio, and a long lifetime.

[ means for solving problems ]

The present invention relates to a liquid crystal composition containing at least one compound selected from compounds represented by formula (1) as a component a and at least one compound selected from compounds represented by formula (2) as a component B, and having positive dielectric anisotropy, and a liquid crystal display element containing the same.

In the formula (1), R ¹ And R ² Hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine; ring A is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chromane-2, 6-diyl or chromane-2, 6-diyl in which at least one hydrogen is substituted by fluorine; z is a linear or branched member ¹ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; x ¹ And X ² Is fluorine or trifluoromethyl, a is 0, 1 or 2;

in the formula (2), R ³ Is alkyl with carbon number of 1 to 12, alkoxy with carbon number of 1 to 12 or alkenyl with carbon number of 2 to 12; ring B is 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene, 2, 6-difluoro-1, 4-phenylene, pyrimidine-2, 5-diyl, 1, 3-dioxane-2, 5-diyl or tetrahydropyran-2, 5-diyl; z is a linear or branched member ² Is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy; x ³ And X ⁴ Is hydrogen or fluorine; y is ¹ Is fluorine, chlorine, alkyl of carbon number 1 to 12 with at least one hydrogen substituted by fluorine or chlorine, alkoxy of carbon number 1 to 12 with at least one hydrogen substituted by fluorine or chlorine, or alkenyloxy of carbon number 2 to 12 with at least one hydrogen substituted by fluorine or chlorine; b is 1, 2,3 or 4.

[ Effect of the invention ]

It is an advantage of the present invention to provide a liquid crystal composition, the polymer fully satisfies at least one of characteristics such as a high upper limit temperature of a nematic phase, a low lower limit temperature of the nematic phase, a low viscosity, an appropriate optical anisotropy, a high dielectric anisotropy, a high elastic constant, a low ratio (gamma 1/K22) of rotational viscosity to elastic constant, a high dielectric constant (epsilon) in the short axis direction, a high ratio (epsilon/delta epsilon) of the dielectric constant to dielectric anisotropy in the short axis direction, a high specific resistance, a high stability to light, and a high stability to heat. Another advantage is to provide a liquid crystal composition having an appropriate balance between at least two of these characteristics. Still another advantage is to provide a liquid crystal display element containing such a composition. Still another advantage is to provide an AM device having characteristics such as a short response time, a high voltage holding ratio, a low threshold voltage, a high contrast ratio, and a long lifetime.

Detailed Description

The usage of the terms in the present specification is as follows. The terms "liquid crystal composition" and "liquid crystal display element" may be simply referred to as "composition" and "element", respectively. The term "liquid crystal display element" is a generic term for liquid crystal display panels and liquid crystal display modules. The "liquid crystalline compound" is a general term for compounds having a liquid crystal phase such as a nematic phase or a smectic phase, and compounds which are not in a liquid crystal phase but are mixed in a composition for the purpose of adjusting characteristics such as a temperature range, viscosity, and dielectric anisotropy of a nematic phase. The compound has a six-membered ring such as 1, 4-cyclohexylene or 1, 4-phenylene, and the molecules (liquid crystal molecules) thereof are rod-like (rod like). The "polymerizable compound" is a compound added for the purpose of forming a polymer in the composition. The liquid crystalline compound having an alkenyl group is not classified into a polymerizable compound in terms of its meaning.

The liquid crystal composition is prepared by mixing a plurality of liquid crystalline compounds. An additive such as an optically active compound or a polymerizable compound is added to the liquid crystal composition as needed. Even in the case where an additive is added, the proportion of the liquid crystalline compound is represented by a mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. The proportion of the additive is represented by mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. That is, the ratio of the liquid crystalline compound or the additive is calculated based on the total mass of the liquid crystalline compound. The proportions of the polymerization initiator and the polymerization inhibitor are exceptionally represented based on the mass of the polymerizable compound.

The "upper limit temperature of the nematic phase" may be simply referred to as "upper limit temperature". The "lower limit temperature of the nematic phase" may be simply referred to as "lower limit temperature". The expression "increase in dielectric anisotropy" means that the value increases positively in a composition having positive dielectric anisotropy, and increases negatively in a composition having negative dielectric anisotropy. The "large voltage holding ratio" means that the device has a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature in the initial stage, and also has a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after long-term use. The properties of the composition or the element are sometimes investigated by time-varying tests.

The compound (1 z) is exemplified. In formula (1 z), the symbols α and β surrounded by a hexagon correspond to ring α and ring β, respectively, and represent a six-membered ring, a condensed ring, and the like. Where subscript 'x' is 2, there are two rings, α. The two groups represented by the two rings a may be the same or may also be different. The rule applies to any two rings a where subscript 'x' is greater than 2. The rules also apply to other tokens such as the bonding base Z. The diagonal line across one side of the loop β indicates that any hydrogen on the loop β can be substituted with a substituent (-Sp-P). The subscript 'y' indicates the number of substituents substituted. Where subscript 'y' is 0, there is no such substitution. When the subscript 'y' is 2 or more, a plurality of substituents (-Sp-P) are present on the ring β. In such cases, the rules "may be the same or may be different" also apply. Furthermore, the rules also apply to the case where the notation of Ra is used for a plurality of compounds.

In formula (1 z), for example, the expression "Ra and Rb are alkyl, alkoxy or alkenyl" means that Ra and Rb are independently selected from the group of alkyl, alkoxy and alkenyl. Here, the group represented by Ra and the group represented by Rb may be the same or may be different.

At least one compound selected from the compounds represented by the formula (1 z) may be simply referred to as "compound (1 z)". The "compound (1 z)" means one compound, a mixture of two compounds or a mixture of three or more compounds represented by the formula (1 z). The same applies to the compounds represented by the other formulae. The expression "at least one compound selected from the group consisting of the compounds represented by the formula (1 z) and the formula (2 z)" means at least one compound selected from the group consisting of the compound (1 z) and the compound (2 z).

The expression "at least one 'a'" means that the number of 'a's is arbitrary. The expression "at least one 'a' may be substituted with 'B' means that the position of 'a' is arbitrary when the number of 'a' is one, and the position thereof may be selected without limitation when the number of 'a' is two or more. Sometimes using "at least one-CH ₂ The expression-may be substituted by-O-. In said case, -CH ₂ -CH ₂ -CH ₂ Can pass through non-contiguous-CH ₂ -conversion to-O-CH by-O-substitution ₂ -O-. However, there is no contiguous-CH ₂ -substituted by-O-. The reason is that: in said substitution, -O-O-CH is formed ₂ - (peroxides).

The alkyl group of the liquid crystalline compound is linear or branched and does not include a cyclic alkyl group. Linear alkyl groups are preferred over branched alkyl groups. The same applies to terminal groups such as alkoxy groups and alkenyl groups. For the configuration of 1, 4-cyclohexylene-related stereo-configuration, the trans-configuration is preferred to the cis-configuration in order to increase the upper limit temperature. Since 2-fluoro-1, 4-phenylene is asymmetric to the left and right, it is present in the left (L) and right (R) directions.

The same applies to divalent radicals such as tetrahydropyran-2, 5-diyl. The same applies to the bonding group (-COO-or-OCO-) such as carbonyloxy.

The present invention is the following items.

Item 1. A liquid crystal composition containing at least one compound selected from the compounds represented by formula (1) as a component a and at least one compound selected from the compounds represented by formula (2) as a component B, and having positive dielectric anisotropy.

In the formula (1), R ¹ And R ² Hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine; ring A is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chromane-2, 6-diyl or chromane-2, 6-diyl in which at least one hydrogen is substituted by fluorine; z ¹ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; x ¹ And X ² Is fluorine or trifluoromethyl, a is 0, 1 or 2;

in the formula (2), R ³ Is carbonAn alkyl group having a number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, or an alkenyl group having a carbon number of 2 to 12; ring B is 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene, 2, 6-difluoro-1, 4-phenylene, pyrimidine-2, 5-diyl, 1, 3-dioxane-2, 5-diyl or tetrahydropyran-2, 5-diyl; z is a linear or branched member ² Is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy; x ³ And X ⁴ Is hydrogen or fluorine; y is ¹ Fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; b is 1, 2,3 or 4.

Item 2. The liquid crystal composition according to item 1, containing at least one compound selected from the group consisting of the compounds represented by formulae (1-1) to (1-7) as the component a.

In the formulae (1-1) to (1-7), R ¹ And R ² Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine.

Item 3. The liquid crystal composition according to item 1 or item 2, wherein the proportion of the component A is in the range of 1 to 20% by mass.

Item 4. The liquid crystal composition according to any one of item 1 to item 3, containing at least one compound selected from the compounds represented by formulae (2-1) to (2-36) as component B.

In the formulae (2-1) to (2-36), R ³ Is alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms or alkenyl group having 2 to 12 carbon atoms.

Item 5. The liquid crystal composition according to any one of item 1 to item 4, wherein the proportion of the component B is in a range of 10 to 85 mass%.

Item 6. The liquid crystal composition according to any one of item 1 to item 5, containing at least one compound selected from the compounds represented by formula (3) as component C.

In the formula (3), R ⁴ And R ⁵ Is C1-12 alkyl, C1-12 alkoxy, C2-12 alkenyl or C2-12 alkenyl with at least one hydrogen substituted by fluorine; ring C and ring D are 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene or 2, 5-difluoro-1, 4-phenylene; z ³ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1, 2 or 3.

Item 7. The liquid crystal composition according to any one of items 1 to 6, containing at least one compound selected from the compounds represented by formulae (3-1) to (3-15) as component C.

In the formulae (3-1) to (3-15), R ⁴ And R ⁵ Is alkyl with carbon number of 1-12, alkoxy with carbon number of 1-12, alkenyl with carbon number of 2-12 or alkenyl with carbon number of 2-12, wherein at least one hydrogen is replaced by fluorine.

Item 8. The liquid crystal composition of item 6 or item 7, wherein the proportion of the component C is in the range of 10 to 75 mass%.

Item 9. The liquid crystal composition according to any one of item 1 to item 8, containing at least one compound selected from the compounds represented by formula (4) as the component D.

In the formula (4), R ⁶ And R ⁷ Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms or alkenyloxy group having 2 to 12 carbon atoms; ring E and ring G are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chromane-2, 6-diyl or chromane-2, 6-diyl in which at least one hydrogen is substituted by fluorine; ring F is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochroman-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl, 4, 6-difluorodibenzofuran-3, 7-diyl, 4, 6-difluorodibenzothiophene-3, 7-diyl, or 1,6, 7-tetrafluoroindan-2, 5-diyl; z ⁴ And Z ⁵ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; d is 0, 1, 2 or 3; e is 0 or 1; the sum of d and e is 3 or less.

Item 10. The liquid crystal composition according to any one of items 1 to 9, containing at least one compound selected from the compounds represented by formulae (4-1) to (4-35) as the component D.

In the formulae (4-1) to (4-35), R ⁶ And R ⁷ Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms or alkenyloxy group having 2 to 12 carbon atoms.

Item 11. The liquid crystal composition of item 9 or item 10, wherein the proportion of component D is in the range of 1 to 50 mass%.

Item 12. A liquid crystal display element comprising the liquid crystal composition according to any one of items 1 to 11.

Item 13 the liquid crystal display element according to item 12, wherein an operation mode of the liquid crystal display element is a TN mode, an ECB mode, an OCB mode, an IPS mode, an FFS mode, or an FPA mode, and a driving method of the liquid crystal display element is an active matrix method.

Item 14. The liquid crystal composition according to any one of item 1 to item 11, for use in a liquid crystal display element of an IPS mode or an FFS mode.

Item 15. Use of a liquid crystal composition according to any one of item 1 to item 11 for a liquid crystal display element.

The present invention also includes the following items. (a) The composition contains one compound, two compounds or three or more compounds selected from additives such as an optically active compound, an antioxidant, an ultraviolet absorber, a delustering agent, a pigment, an antifoaming agent, a polymerizable compound, a polymerization initiator, a polymerization inhibitor and a polar compound. (b) an AM element comprising the composition. (c) The composition further contains a polymerizable compound, and a polymer-stabilized oriented (PSA) AM element containing the composition. (d) An AM element of Polymer Stable Alignment (PSA) type, comprising the composition, wherein a polymerizable compound in the composition is polymerized. (e) An element comprising said composition and having a pattern of PC, TN, STN, ECB, OCB, IPS, VA, FFS or FPA. (f) a permeable element comprising said composition. (g) Use of said composition as a composition having a nematic phase. (h) Use of an optically active composition obtained by adding an optically active compound to the composition.

The composition of the present invention is illustrated in the following order. First, the structure of the composition will be explained. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element will be described. Thirdly, combinations, preferable ratios and their references of the component compounds in the composition are explained. Fourthly, preferred forms of the component compounds will be explained. Fifth, preferred component compounds are shown. Sixth, additives that can be added to the composition will be described. Seventh, a method for synthesizing the component compound will be explained. Finally, the use of the composition is illustrated.

First, the structure of the composition will be explained. The composition contains a plurality of liquid crystalline compounds. The composition may also contain additives. The additive is an optically active compound, an antioxidant, an ultraviolet absorber, a matting agent, a coloring matter, an antifoaming agent, a polymerizable compound, a polymerization initiator, a polymerization inhibitor, a polar compound, or the like. From the viewpoint of the liquid crystalline compound, the compositions are classified into composition a and composition B. The composition a may contain other liquid crystalline compounds, additives, and the like in addition to the liquid crystalline compound selected from the group consisting of the compound (1), the compound (2), the compound (3), and the compound (4). The "other liquid crystalline compound" is a liquid crystalline compound different from the compound (1), the compound (2), the compound (3) and the compound (4). Such compounds are mixed in the composition for the purpose of further adjusting the properties.

The composition B substantially contains only a liquid crystalline compound selected from the group consisting of the compound (1), the compound (2), the compound (3) and the compound (4). "substantially" means that the composition B may contain additives but does not contain other liquid crystalline compounds. The amount of ingredients of composition B is low compared to composition a. From the viewpoint of cost reduction, composition B is superior to composition a. From the viewpoint that the characteristics can be further adjusted by mixing other liquid crystalline compounds, the composition a is superior to the composition B.

Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element will be described. The main properties of the component compounds are summarized in Table 2. In the notation of Table 2, L means large or high, M means medium, and S means small or low. The notation L, M, S is a classification based on qualitative comparison between the component compounds, and the notation 0 (zero) means less than S.

TABLE 2 Properties of liquid crystalline Compounds

Characteristics of	Compound (1)	Compound (2)	Compound (3)	Compound (4)
					Upper limit temperature	M～L	S～L	S～L	S～M
Viscosity of the oil	L	M～L	S～M	M～L
					Optical anisotropy	L	M～L	S～L	M～L
Dielectric anisotropy	L ¹⁾	M～L	0	M～L ¹⁾
					Specific resistance	L	L	L	L
Spring constant	L	S～M	S～L	S～M

1) The value of the dielectric anisotropy is negative, and the sign indicates the magnitude of the absolute value

The main effects of the component compounds are as follows. The compound (1) increases the elastic constant and the dielectric constant in the minor axis direction. The compound (2) improves the dielectric anisotropy. The compound (3) lowers the viscosity or raises the upper temperature. The compound (4) increases the dielectric constant in the minor axis direction or decreases the lower limit temperature.

Thirdly, combinations of the component compounds in the composition, preferable ratios and their basis are explained. Preferred combinations of the component compounds in the composition are compound (1) + compound (2), compound (1) + compound (2) + compound (3), compound (1) + compound (2) + compound (4), or compound (1) + compound (2) + compound (3) + compound (4). Particularly preferred combinations are compound (1) + compound (2) + compound (3) or compound (1) + compound (2) + compound (3) + compound (4).

The preferable proportion of the compound (1) is about 1% by mass or more in order to increase the elastic constant and the dielectric constant in the minor axis direction, and the preferable proportion of the compound (1) is about 20% by mass or less in order to lower the lower limit temperature. A more preferable ratio is in the range of about 5% by mass to about 20% by mass. A particularly preferred ratio is in the range of about 5% to about 15% by mass.

The preferable proportion of the compound (2) is about 10% by mass or more for improving the dielectric anisotropy, and the preferable proportion of the compound (2) is about 85% by mass or less for lowering the lower limit temperature. Further, the preferable ratio is in the range of about 10 to about 70 mass%. A particularly preferred ratio is in the range of about 10% by mass to about 50% by mass.

The preferable proportion of the compound (3) is about 10% by mass or more in order to lower the viscosity or to raise the upper limit temperature, and the preferable proportion of the compound (3) is about 75% by mass or less in order to raise the dielectric anisotropy. Further, the preferable ratio is in the range of about 20 to about 75 mass%. A particularly preferred ratio is in the range of about 30% by mass to about 70% by mass.

The preferable proportion of the compound (4) is about 1% by mass or more in order to increase the dielectric constant in the minor axis direction, and the preferable proportion of the compound (4) is about 50% by mass or less in order to lower the lower limit temperature. Further, the preferable ratio is in the range of about 1% by mass to about 35% by mass. A particularly preferred ratio is in the range of about 1% by mass to about 20% by mass.

Fourth, preferred embodiments of the component compounds will be described. In the formulae (1), (2), (3) and (4), R ¹ And R ² Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine. For lowering the lower limit temperature, R is preferable ¹ Or R ² R is an alkenyl group having 1 to 12 carbon atoms and is preferably selected to increase the dielectric constant in the minor axis direction ¹ Or R ² Is an alkoxy group having 1 to 12 carbon atoms. Further preferred is R ¹ Or R ² Is alkoxy with 2 to 4 carbon atoms. R ³ An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms. For improved stability, R is preferred ³ Is an alkyl group having 1 to 12 carbon atoms. R ⁴ And R ⁵ Is alkyl with carbon number of 1-12, alkoxy with carbon number of 1-12, alkenyl with carbon number of 2-12 or alkenyl with carbon number of 2-12, wherein at least one hydrogen is replaced by fluorine. For improved stability, R is preferred ⁴ Or R ⁵ Is alkyl of carbon number 1 to 12, and R is preferably selected to reduce viscosity ⁴ Or R ⁵ Is an alkenyl group having 2 to 12 carbon atoms. R ⁶ And R ⁷ Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms or alkenyloxy group having 2 to 12 carbon atoms. For improved stability, R is preferred ⁶ Or R ⁷ Is alkyl of carbon number 1 to 12, and R is preferably selected to reduce viscosity ⁶ Or R ⁷ R is an alkenyl group having 2 to 12 carbon atoms and is preferably selected to increase the dielectric constant in the minor axis direction ⁶ Or R ⁷ Is an alkoxy group having 1 to 12 carbon atoms.

Preferred alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl. Further preferred alkyl groups for reducing the viscosity are methyl, ethyl, propyl, butyl or pentyl.

Preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy. Further preferred alkoxy groups for reducing the viscosity are methoxy or ethoxy.

Preferred alkenyl groups are vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl or 5-hexenyl. Further preferred alkenyl groups for reducing the viscosity are vinyl, 1-propenyl, 3-butenyl or 3-pentenyl. The preferred steric configuration of-CH = CH-in these alkenyl groups depends on the position of the double bond. For reasons of viscosity reduction and the like, the trans configuration is preferred among alkenyl groups such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl, 3-hexenyl. Among alkenyl groups such as 2-butenyl, 2-pentenyl, 2-hexenyl, the cis configuration is preferred.

Preferred alkenyloxy groups are vinyloxy, allyloxy, 3-butenyloxy, 3-pentenyloxy or 4-pentenyloxy. Further, in order to reduce the viscosity, allyloxy or 3-butenyloxy is more preferable.

Preferred examples of alkyl groups in which at least one hydrogen is substituted by fluorine or chlorine are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl, 7-fluoroheptyl or 8-fluorooctyl. Further preferable examples of the compound for improving the dielectric anisotropy include 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl and 5-fluoropentyl.

Preferred examples of alkenyl groups in which at least one hydrogen is substituted by fluorine or chlorine are 2, 2-difluorovinyl, 3-difluoro-2-propenyl, 4-difluoro-3-butenyl, 5-difluoro-4-pentenyl or 6, 6-difluoro-5-hexenyl. Further preferable examples for lowering the viscosity are 2, 2-difluorovinyl group and 4, 4-difluoro-3-butenyl group.

Ring A, ring E and ring G are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chromane-2, 6-diyl or chromane-2, 6-diyl in which at least one hydrogen is substituted by fluorine. Preferred examples of "1, 4-phenylene in which at least one hydrogen is substituted with fluorine" are 2-fluoro-1, 4-phenylene or 2, 3-difluoro-1, 4-phenylene. The ring A is preferably a 1, 4-cyclohexylene group for the purpose of reducing the viscosity, and a 1, 4-phenylene group for the purpose of improving the optical anisotropy. The ring E or G is preferably 1, 4-cyclohexylene for lowering the viscosity, tetrahydropyran-2, 5-diyl for increasing the dielectric constant in the short axis direction, and 1, 4-phenylene for increasing the optical anisotropy.

Tetrahydropyran-2, 5-diyl is

Preferably a

Ring F is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl (FLF 4), 4, 6-difluorodibenzofuran-3, 7-diyl (DBFF 2), 4, 6-difluorodibenzothiophene-3, 7-diyl (DBTF 2), or 1,6, 7-tetrafluoroindan-2, 5-diyl (InF 4).

The preferred ring F is 2, 3-difluoro-1, 4-phenylene for lowering the viscosity, and 4, 6-difluorodibenzothiophene-3, 7-diyl for increasing the dielectric constant in the minor axis direction.

Ring B is 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene, 2, 6-difluoro-1, 4-phenylene, pyrimidine-2, 5-diyl, 1, 3-dioxane-2, 5-diyl or tetrahydropyran-2, 5-diyl. The ring B is preferably 1, 4-cyclohexylene for increasing the upper limit temperature, 1, 4-phenylene for increasing the optical anisotropy, and 2, 6-difluoro-1, 4-phenylene for increasing the dielectric anisotropy. Tetrahydropyran-2, 5-diyl is

Preferably a

And ring C and ring D are 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene or 2, 5-difluoro-1, 4-phenylene. The preferred ring C or D is 1, 4-cyclohexylene for lowering the viscosity or for raising the upper temperature limit, and 1, 4-phenylene or 2-fluoro-1, 4-phenylene for raising the optical anisotropy or for lowering the lower temperature limit.

Z ¹ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z ¹ Is a single bond, and Z is preferably a bond for lowering the lower limit temperature ¹ Is ethylene, and Z is preferably Z for increasing the dielectric constant in the minor axis direction ¹ Is methyleneoxy or carbonyloxy. Z ² Is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy. For reducing viscosity, Z is preferred ² Is a single bond, and Z is preferably a bond for improving dielectric anisotropy ² Is difluoromethyleneoxy. Z ³ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z ³ Is a single bond. Z is a linear or branched member ⁴ And Z ⁵ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing viscosity, Z is preferred ⁴ Or Z ⁵ Is a single bond, and Z is preferably Z for lowering the lower limit temperature ⁴ Or Z ⁵ Is ethylene, and Z is preferably Z for increasing the dielectric constant in the minor axis direction ⁴ Or Z ⁵ Is a methyleneoxy group.

X ¹ And X ² Is fluorine or trifluoromethyl. For reducing the viscosity, preferred is X ¹ Or X ² Is fluorine.

X ³ And X ⁴ Is hydrogen or fluorine. For improving the dielectric anisotropy, X is preferable ³ Or X ⁴ Is fluorine.

Y ¹ Is fluorine, chlorine, at least one hydrogen via fluorineOr a chlorine-substituted alkyl group having 1 to 12 carbon atoms, at least one hydrogen-substituted alkoxy group having 1 to 12 carbon atoms which is substituted with fluorine or chlorine, or at least one hydrogen-substituted alkenyloxy group having 2 to 12 carbon atoms which is substituted with fluorine or chlorine. For improving the dielectric anisotropy, Y is preferable ¹ Is fluorine, an alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted by fluorine or chlorine, or an alkoxy group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted by fluorine or chlorine. A preferable example of the alkyl group in which at least one hydrogen is substituted with fluorine or chlorine is a trifluoromethyl group. A preferred example of an alkoxy group in which at least one hydrogen is substituted by fluorine or chlorine is a trifluoromethoxy group.

a is 0, 1 or 2. For lowering the viscosity, a is preferably 0, and for raising the upper limit temperature, a is preferably 1.b is 1, 2,3 or 4. For lowering the viscosity, b is preferably 2, and for improving the dielectric anisotropy, b is preferably 3.c is 1, 2 or 3. For lowering the viscosity, c is preferably 1, and for raising the upper limit temperature, c is preferably 2 or 3.d is 0, 1, 2 or 3, e is 0 or 1, and the sum of d and e is 3 or less. For lowering the viscosity, d is preferably 1, and for raising the upper limit temperature, d is preferably 2 or 3. For lowering the viscosity, e is preferably 0, and for lowering the lower limit temperature, e is preferably 1.

Fifth, preferred component compounds are shown. Preferred compound (1) is the compound (1-1) to the compound (1-7) described in the item 2. Among these compounds, it is particularly preferable that at least one of the components A is the compound (1-1). Component A preferably contains at least two compounds (1).

Preferred compound (2) is the compound (2-1) to the compound (2-36) described in the item 4. Of these compounds, it is preferable that at least one of the components B is a compound (2-2), a compound (2-8), a compound (2-13), a compound (2-15), a compound (2-16), a compound (2-17), a compound (2-19), a compound (2-23), a compound (2-24), a compound (2-25), a compound (2-27), a compound (2-28), a compound (2-30) or a compound (2-31). Preferably, at least two of the components B are a combination of the compound (2-2) and the compound (2-19), the compound (2-2) and the compound (2-24), the compound (2-2) and the compound (2-25), the compound (2-2) and the compound (2-30), the compound (2-19) and the compound (2-24), the compound (2-19) and the compound (2-25), or the compound (2-19) and the compound (2-30). Particularly preferably, at least two of the components B are a combination of the compounds (2-19) and the compounds (2-30).

Preferred compound (3) is the compound (3-1) to the compound (3-15) described in the item 7. Of these compounds, it is preferable that at least one of the components C is the compound (3-1), the compound (3-3), the compound (3-4), the compound (3-5), the compound (3-7), the compound (3-8), the compound (3-10) or the compound (3-12). Preferably, at least two of the components C are a combination of the compound (3-1) and the compound (3-3), the compound (3-1) and the compound (3-4), the compound (3-1) and the compound (3-5), the compound (3-1) and the compound (3-7), the compound (3-1) and the compound (3-8), the compound (3-1) and the compound (3-10), the compound (3-1) and the compound (3-12), the compound (3-4) and the compound (3-5), the compound (3-4) and the compound (3-7), the compound (3-7) and the compound (3-10), or the compound (3-7) and the compound (3-12). Particularly preferably R ⁴ And R ⁵ At least one of (3) is an alkenyl group having 2 to 5 carbon atoms. The proportion of these compounds is preferably 20% by mass or more, and particularly preferably 30% by mass or more.

Preferred compound (4) is the compound (4-1) to the compound (4-35) described in the item 10. Of these compounds, it is preferable that at least one of the components D is the compound (4-1), the compound (4-2), the compound (4-3), the compound (4-6), the compound (4-8), the compound (4-9), the compound (4-10), the compound (4-14), the compound (4-19) or the compound (4-34). Preferably, at least two of the components D are a combination of the compounds (4-1) and (4-8), the compounds (4-1) and (4-34), the compounds (4-2) and (4-9), the compounds (4-3) and (4-10), the compounds (4-8) and (4-14), the compounds (4-8) and (4-19), the compounds (4-8) and (4-34), the compounds (4-14) and (4-19), the compounds (4-14) and (4-34) or the compounds (4-19) and (4-34).

Sixth, additives that can be added to the composition will be described. Such additives include optically active compounds, antioxidants, ultraviolet absorbers, delustering agents, pigments, antifoaming agents, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, and the like. An optically active compound is added to the composition for the purpose of inducing a helical structure of liquid crystal molecules to impart a twist angle (torsion angle). Examples of such compounds are compound (6-1) to compound (6-5). The preferable proportion of the optically active compound is about 5% by mass or less. Further, the preferable ratio is in the range of about 0.01 to about 2 mass%.

In order to prevent a decrease in specific resistance due to heating in the atmosphere or to maintain a large voltage holding ratio at room temperature and at a temperature close to the upper limit temperature even after the device is used for a long time, an antioxidant such as the compounds (7-1) to (7-3) may be further added to the composition.

Since the compound (7-2) has low volatility, it is effective for maintaining a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after the device is used for a long time. In order to obtain the above effects, the preferable proportion of the antioxidant is about 50ppm or more, and in order not to lower the upper limit temperature or to raise the lower limit temperature, the preferable proportion of the antioxidant is about 600ppm or less. Even more preferred ratios range from about 100ppm to about 300 ppm.

Preferable examples of the ultraviolet absorber include benzophenone derivatives, benzoate derivatives, triazole derivatives and the like. Further, light stabilizers such as hindered amines are also preferred. Preferable examples of the light stabilizer are compound (8-1) to compound (8-16) and the like. The preferable proportion of these absorbents or stabilizers is about 50ppm or more in order to obtain the above effects, and about 10000ppm or less in order not to lower the upper limit temperature or not to raise the lower limit temperature. Even more preferred ratios range from about 100ppm to about 10000 ppm.

The matting agent is a compound that receives light energy absorbed by the liquid crystalline compound and converts the light energy into thermal energy to prevent decomposition of the liquid crystalline compound. Preferable examples of the matting agent are a compound (9-1) to a compound (9-7) and the like. The preferred proportion of these matting agents is about 50ppm or more for obtaining the above-mentioned effects, and about 20000ppm or less for not raising the lower limit temperature. Even more preferred ratios range from about 100ppm to about 10000 ppm.

In order to be suitable for a guest-host (GH) mode element, a dichroic dye (dichromatic dye) such as an azo dye or an anthraquinone dye is added to the composition. The preferable ratio of the pigment ranges from about 0.01% by mass to about 10% by mass. In order to prevent bubbling, an antifoaming agent such as dimethylsilicone oil or methylphenylsilicone oil is added to the composition. The preferable ratio of the defoaming agent is about 1ppm or more for obtaining the above effect, and about 1000ppm or less for preventing display failure. Even more preferred ratios range from about 1ppm to about 500 ppm.

Polymerizable compounds are used to adapt to polymer-stabilized alignment (PSA) type devices. Preferable examples of such polymerizable compounds are compounds such as acrylic acid esters, methacrylic acid esters, vinyl compounds, vinyloxy compounds, propylene ethers, epoxy compounds (oxetane ) and vinyl ketones. Further preferred are derivatives of acrylic acid esters or methacrylic acid esters. The preferable ratio is about 10% by mass or more based on the total mass of the polymerizable compound. A more preferable ratio is about 50% by mass or more. A particularly preferred ratio is about 80% by mass or more. The most preferable ratio is 100 mass%.

When the polymerizable compound is stored, a polymerization inhibitor may be added to prevent polymerization. The polymerizable compound is usually added to the composition in a state where the polymerization inhibitor is not removed. Examples of the polymerization inhibitor are hydroquinone derivatives such as hydroquinone and methyl hydroquinone, 4-t-butyl catechol, 4-methoxyphenol, phenothiazine and the like.

The polar compound is an organic compound having polarity. Here, a compound having an ionic bond is not included. Atoms such as oxygen, sulfur and nitrogen are negatively charged and tend to have a partial negative charge. Carbon and hydrogen are neutral or tend to have a partial positive charge. Polarity arises because part of the charge is distributed unequally among the atoms of different species in the compound. For example, the polar compound has-OH, -COOH, -SH, -NH ₂ At least one of partial structures such as NH and N-.

Seventh, a method for synthesizing the component compound will be explained. These compounds can be synthesized by known methods. A synthesis method is exemplified. The compound (1-1) is synthesized by the method described in Japanese patent laid-open No. 8-53672. Compound (2-19) is synthesized by the method described in Japanese patent laid-open No. Hei 10-251186. The compound (3-1) is synthesized by the method described in Japanese patent laid-open No. 9-77692. The compound (4-1) is synthesized by the method described in Japanese patent laid-open publication No. 2-503441. Compound (7-1) is available from Sigma Aldrich Corporation. Compound (7-2) and the like are synthesized by the method described in the specification of U.S. Pat. No. 3,3660505.

Compounds not described in the synthesis method can be synthesized by the methods described in the following protocol: organic Synthesis (Organic Syntheses, john Wiley & Sons, inc), "Organic Reactions (Organic Reactions, john Wiley & Sons, inc)," Comprehensive Organic Synthesis (Comprehensive Organic Synthesis, pegman Press), "new experimental chemistry lecture (pill). The compositions are prepared by known methods from the compounds obtained in the manner described. For example, the component compounds are mixed and then dissolved in each other by heating.

Finally, the use of the composition is illustrated. The composition has primarily a lower temperature limit of about-10 ℃ or less, an upper temperature limit of about 70 ℃ or more, and an optical anisotropy in a range from about 0.07 to about 0.20. A composition having an optical anisotropy in the range of about 0.08 to about 0.25 may also be prepared by controlling the proportions of the component compounds, or by mixing other liquid crystalline compounds. Compositions having optical anisotropy in the range of about 0.10 to about 0.30 may also be prepared by trial and error. The device containing the composition has a large voltage holding ratio. The composition is suitable for AM elements. The composition is particularly suitable for transmissive AM elements. The composition can be used as a composition having a nematic phase, and can be used as an optically active composition by adding an optically active compound.

The composition can be used in AM elements. And can also be used for PM elements. The composition can be used for AM elements and PM elements having modes such as PC, TN, STN, ECB, OCB, IPS, FFS, VA and FPA. Particularly preferably for AM elements having TN, OCB, IPS mode or FFS mode. In an AM element having an IPS mode or an FFS mode, the alignment of liquid crystal molecules may be parallel to a glass substrate or may be perpendicular to the glass substrate when no voltage is applied. These elements may be reflective, transmissive or transflective. Preferably for use in transmissive devices. It can also be used for an amorphous silicon-TFT element or a polysilicon-TFT element. The composition may be used for a device of a Nematic Curvilinear Aligned Phase (NCAP) type prepared by microencapsulation (microencapsulation) or a device of a Polymer Dispersed (PD) type in which a three-dimensional network polymer is formed in the composition.

[ examples ]

The present invention will be further described in detail by way of examples. The present invention is not limited by these examples. The invention comprises a mixture of the composition of example 1 and the composition of example 2. The invention also includes mixtures of at least two of the compositions of the examples. The synthesized compound is identified by Nuclear Magnetic Resonance (NMR) analysis or the like. The properties of the compounds, compositions and devices were measured by the methods described below.

NMR analysis: DRX-500 manufactured by Bruker BioSpin was used for the measurement. ¹ In the measurement of H-NMR, a sample was dissolved in CDCl ₃ The measurement was performed in the deuterated solvent at room temperature under conditions of 500MHz and 16 cumulative times. Tetramethylsilane was used as an internal standard. ¹⁹ In the measurement of F-NMR, CFCl was used ₃ As an internal standard, the number of times is accumulated to 24 times. In the description of the nmr spectra, s is a singlet (singlet), d is a doublet (doublt), t is a triplet (triplet), q is a quartet (quatet), quin is a quintet (quintet), sex is a sextant (sextet), m is a multiplet (multiplet), and br is a broad (broad).

Gas chromatographic analysis: for measurement, a GC-14B gas chromatograph manufactured by Shimadzu corporation was used. The carrier gas was helium (2 mL/min). The sample vaporizer was set at 280 ℃ and the detector (flame ionization detector, FID) was set at 300 ℃. The separation of the component compounds was carried out by using a capillary column DB-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm; fixing liquid phase is dimethylpolysiloxane; non-polar) manufactured by Agilent Technologies Inc. After the column was held at 200 ℃ for 2 minutes, the temperature was raised to 280 ℃ at a rate of 5 ℃/min. After preparing the sample into an acetone solution (0.1 mass%), 1. Mu.L of the acetone solution was injected into the sample vaporization chamber. The record is a C-R5A chromatograph module (Chromatopac) manufactured by Shimadzu corporation or an equivalent thereof. The obtained gas chromatogram showed the retention time of the peak corresponding to the component compound and the area of the peak.

Chloroform, hexane, and the like can be used as a solvent for diluting the sample. To separate the component compounds, the following capillary column may be used. HP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Agilent Technologies Inc., rtx-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Rasteck Corporation, BP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Australian SGE International Pty.Ltd, and BP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by SGE International Ltd. For the purpose of preventing overlapping of the compound peaks, capillary columns CBP1-M50-025 (length 50M, inner diameter 0.25mm, film thickness 0.25 μ M) manufactured by Shimadzu corporation were used.

The ratio of the liquid crystalline compound contained in the composition can be calculated by the following method. The mixture of liquid crystalline compounds was analyzed by gas chromatography (FID). The area ratio of the peaks in the gas chromatogram corresponds to the ratio of the liquid crystalline compound. When the capillary column described above is used, the correction coefficient of each liquid crystalline compound can be regarded as 1. Therefore, the ratio (% by mass) of the liquid crystalline compound can be calculated from the area ratio of the peak.

Measurement of the sample: in the measurement of the properties of the composition or the element, the composition is used as a sample as it is. In order to measure the characteristics of the compound, a sample for measurement was prepared by mixing the compound (15 mass%) in a mother liquid crystal (85 mass%). From the values obtained by the measurement, the characteristic values of the compounds were calculated by an extrapolation method (extrapolation method). (extrapolated value) = { (measurement value of sample) — 0.85 × (measurement value of mother liquid crystal) }/0.15. When a smectic phase (or crystal) precipitates at 25 ℃ at the ratio, the ratio of the compound to the mother liquid crystal is set at 10 mass%: 90% by mass and 5% by mass: 95% by mass and 1% by mass: the order of 99 mass% was changed. The values of the upper limit temperature, optical anisotropy, viscosity and dielectric anisotropy relating to the compound were determined by the extrapolation method.

The following mother liquid crystal was used. The proportion of the component compounds is represented by mass%.

The determination method comprises the following steps: the characteristics were measured by the following methods. These methods are mostly described in JEITA standard (JEITA. ED-2521B) examined and established by the Japan electronic Information Technology Industries Association (JEITA), or modified. The TN cell used for the measurement was not mounted with a Thin Film Transistor (TFT).

(1) Upper limit temperature of nematic phase (NI;. Degree. C.): the sample was placed on a hot plate of a melting point measuring apparatus equipped with a polarizing microscope, and heated at a rate of 1 ℃/min. The temperature at which a portion of the sample changes from a nematic phase to an isotropic liquid is measured. The upper limit temperature of the nematic phase may be simply referred to as "upper limit temperature".

(2) Lower limit temperature (T) of nematic phase _C (ii) a C.): a sample having a nematic phase was placed in a glass bottle, and the liquid crystal phase was observed after 10 days of storage in a freezer at 0 ℃, -10 ℃, -20 ℃, -30 ℃, and-40 ℃. For example, when the sample is kept in a nematic phase at-20 ℃ and changed to a crystalline or smectic phase at-30 ℃, T is adjusted _C Is reported as < -20 ℃. The lower limit temperature of the nematic phase may be simply referred to as "lower limit temperature".

(3) Viscosity (bulk viscosity;. Eta.;. Measured at 20 ℃ C.;. MPas): for the measurement, an E-type rotational viscometer manufactured by tokyo counter gmbh was used.

(4) Viscosity (rotational viscosity; γ 1; measured at 25 ℃; mPas): the measurement was carried out according to the method described in Molecular Crystals and Liquid Crystals (Molecular Crystals and Liquid Crystals), vol.259,37 (1995) of M.J. well (M.Imai) et al. A sample was placed in a TN cell having a twist angle of 0 ℃ and a gap (cell gap) of 5 μm between two glass substrates. In the range of 16V to 19.5V, a voltage is applied to the element in stages in units of 0.5V. After 0.2 second of no voltage application, voltage application was repeated under the conditions of only 1 square wave (square pulse; 0.2 second) application and no voltage application (2 seconds). The peak current (peak current) and peak time (peak time) of the transient current (transient current) generated by the application are measured. The values of rotational viscosity were obtained from these measured values and the calculation formula (10) described on page 40 in the article by M. The value of the dielectric anisotropy required for the calculation was determined by the following method using a device for measuring the rotational viscosity.

(5) Optical anisotropy (refractive index anisotropy; Δ n; measured at 25 ℃): the measurement was performed using light having a wavelength of 589nm by an Abbe refractometer having a polarizing plate attached to an eyepiece lens. After rubbing the surface of the primary prism in one direction, the sample was dropped onto the primary prism. The refractive index n/is measured when the direction of polarization is parallel to the direction of rubbing. The refractive index n ″) is measured when the direction of the polarized light is perpendicular to the direction of the friction. The value of the optical anisotropy is calculated from the equation of Δ n = n/n ×.

(6) Dielectric anisotropy (. DELTA.. Di-elect cons.; measured at 25 ℃): a sample was placed in a TN cell having a cell gap of 9 μm and a twist angle of 80 degrees between two glass substrates. A sine wave (10V, 1 kHz) was applied to the cell, and the dielectric constant (. Epsilon. /) in the long axis direction of the liquid crystal molecules was measured after 2 seconds. Sine wave (0.5V, 1 kHz) was applied to the element, and the dielectric constant (∈ ∈ in the short axis direction of the liquid crystal molecules was measured after 2 seconds. The value of the dielectric anisotropy is calculated from the formula Δ ∈ = ∈/∈ ″) j.

(7) Threshold voltage (Vth; measured at 25 ℃; V): for the measurement, a Liquid Crystal Display (LCD) 5100 type luminance meter manufactured by Otsuka electronics Ltd was used. The light source is a halogen lamp. The sample was placed in an FFS cell having a gap (cell gap) of 3.2 (μm) between two glass substrates. The voltage (32 Hz, rectangular wave) applied to the element was increased from 0V to 10V in a stepwise manner in units of 0.01V. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. A voltage-transmittance curve was prepared in which the transmittance was 100% when the amount of light was the maximum and the transmittance was 0% when the amount of light was the minimum. The threshold voltage is represented by a voltage at which the transmittance becomes 90%.

(8) Voltage holding ratio (VHR-9; measured at 25;%): the TN element used for the measurement had a polyimide alignment film, and the interval (cell gap) between the two glass substrates was 5 μm. The element is sealed with an adhesive cured with ultraviolet rays after the sample is placed. The TN cell is charged by applying a pulse voltage (1V, 60 μ sec). The decayed voltage was measured by a high-speed voltmeter over a period of 1000 milliseconds, and the area a between the voltage curve per unit cycle and the horizontal axis was determined. The area B is the area without attenuation. The voltage holding ratio is expressed by a percentage of the area a to the area B.

(9) Voltage holding ratio (VHR-10; measured at 60;%): the voltage holding ratio was measured in the same procedure as described above except that the measurement was performed at 60 ℃ instead of 25 ℃. The obtained value is represented by VHR-10.

(10) Voltage holding ratio (VHR-11; measured at 60;%): after irradiation with ultraviolet light, the voltage holding ratio was measured to evaluate the stability to ultraviolet light. The TN cells used for the measurement had a polyimide alignment film and a cell gap of 5 μm. The sample was injected into the cell and irradiated with 5mW/cm ² For 167 minutes. The light source was black light (Black light) manufactured by Eyegraphics, inc., F40T10/BL (Peak wavelength of 369 nm), and the interval between the element and the light source was 5mm. In the measurement of VHR-11, the voltage of decay was measured over a period of 1000 milliseconds. Compositions with large VHR-11 have a large stability to UV light.

(11) Voltage holding ratio (VHR-12; measured at 60;%): the TN cells impregnated with the samples were heated in a thermostatic bath at 120 ℃ for 20 hours, and then the voltage holding ratio was measured to evaluate the stability to heat. In the measurement of VHR-12, the voltage of decay was measured over a period of 1000 milliseconds. Compositions with large VHR-12 have a large stability to heat.

(12) Voltage holding ratio (VHR-13; measured at 60 ℃.): the TN elements impregnated with the samples were heated in a thermostat at 100 ℃ for three weeks, and then the voltage holding ratio was measured to evaluate the stability to heat. In the measurement of VHR-13, the voltage at which the voltage decays was measured over a period of 1000 milliseconds. Compositions with large VHR-13 have a large stability to heat.

(13) Voltage holding ratio (VHR-14; measured at 60;%): after the TN cell injected with the sample was left standing on a backlight for two weeks, the voltage holding ratio was measured to evaluate the stability against the backlight. In the measurement of VHR-14, the voltage of decay was measured over a period of 1000 milliseconds. Compositions with large VHR-14 have a large stability against backlighting.

(14-1) response time (. Tau. (25); measured at 25 ℃ C.; ms): for the measurement, an LCD5100 type luminance meter manufactured by Otsuka electronics Co., ltd was used. The light source is a halogen lamp. The Low pass filter (Low-pass filter) was set to 5kHz. A sample was placed in an FFS element having a spacing (cell gap) of 3.2 μm between two glass substrates. A square wave (60 Hz, 5V, 0.5 sec) was applied to the element. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. When the light amount is the maximum, the transmittance is regarded as 100%, and when the light amount is the minimum, the transmittance is regarded as 0%. The rise time (τ r: rise time; milliseconds) is the time required for the transmittance to change from 90% to 10%. The fall time (τ f: fall time; milliseconds) is the time required for the transmittance to change from 10% to 90%. The response time is represented by the sum of the rise time and the fall time found in the above manner.

(14-2) response time (. Tau. (-30); measured at-30 ℃ C.; ms): the same as (14-1) except that the measurement was carried out at-30 ℃ and the conditions for applying a rectangular wave (60 Hz, 5V, 15 seconds) were changed.

(15) Elastic constant (K11: splay (spring) elastic constant, K22: twist (twist) elastic constant, K33: bend (bend) elastic constant; measured at 25 ℃; pN): for the measurement, an LCR meter model HP4284A manufactured by Yokogawa Hewlett Packard, inc. was used. A sample was placed in a horizontally oriented cell having a gap (cell gap) of 20 μm between two glass substrates. A charge of 0 to 20 volts is applied to the element, and the electrostatic capacitance and applied voltage are measured. The values of the electrostatic capacitance (C) and the applied voltage (V) measured were fitted using the expressions (2.98) and (2.101) on page 75 of the manual for Liquid Crystal devices (Liquid Crystal Device Handbook) (news agency, japan), and the values of K11 and K33 were obtained from the expressions (2.99). Then, the obtained values of K11 and K33 were used in equation (3.18) on page 171 of "liquid crystal device manual" (japanese industrial news agency) to calculate K22.

(16) Specific resistance (. Rho.; measured at 25 ℃ C.;. Omega. Cm): 1.0mL of the sample was injected into a container equipped with an electrode. A DC voltage (10V) was applied to the vessel, and a DC current after 10 seconds was measured. The specific resistance is calculated according to the following equation. (specific resistance) = (voltage) × (capacitance of container) }/{ (direct current) × (dielectric constant of vacuum) }.

(17) Pitch (P; measured at room temperature; μm): the pitch is measured using the wedge method. Refer to page 196 of "liquid Crystal Messaging" (published in 2000, wanshan). The sample was poured into a wedge-shaped cell, and after standing at room temperature for 2 hours, the interval (d 2-d 1) between disclination lines was observed by a polarization microscope (Nikon (Strand), trade name MM40/60 series). The pitch (P) is calculated from the following equation which expresses the angle of the wedge element as θ. P =2 × (d 2-d 1) × tan θ.

(18) Dielectric constant (. Epsilon. DELTA.; measured at 25 ℃) in the minor axis direction: a sample was placed in a TN cell having a cell gap (cell gap) of 9 μm and a twist angle of 80 degrees between two glass substrates. Sine waves (0.5V, 1 kHz) were applied to the element, and the dielectric constant in the short axis direction of the liquid crystal molecules (∈ j) was measured after 2 seconds.

(19) Frequency dependence of dielectric anisotropy (F10; measured at-20 ℃): a sample was placed in a TN cell having a cell gap (cell gap) of 9 μm and a twist angle of 80 degrees between two glass substrates. Sine waves (0.5V, 100 Hz-200 Hz-500 Hz-800 Hz-1 kHz-2 kHz-5 kHz-8 kHz-10 kHz-20 kHz-50 kHz-80 kHz-100 kHz) were applied to the elements, and the dielectric constant (. Epsilon. Quadrature. Was measured in the short axis direction of the liquid crystal molecules after 2 seconds. The frequency at which the dielectric anisotropy was reduced by 10% with respect to the dielectric anisotropy at 100Hz was designated as F10. The larger F10, the smaller the frequency dependence.

Examples of compositions are shown below. The component compounds are represented by symbols based on the definitions in table 3 below. In Table 3, the configuration of the 1, 4-cyclohexylene group-related solid is trans configuration. The numbers in parentheses following the labeled compounds indicate the chemical formulae to which the compounds belong. The symbol (-) indicates other liquid crystalline compounds. The proportion (percentage) of the liquid crystalline compound is a mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. Finally, the values of the properties of the composition are summarized.

TABLE 3 expression of compounds using notation

R-(A ₁ )-Z ₁ -·····-Z _n -(A _n )-R′

Comparative example 1

International publication No. 2014-045905 (patent document 4) discloses a liquid crystal composition containing a compound having positive dielectric anisotropy (compound (2-16) and the like) and a compound having negative dielectric anisotropy (compound (4-8) and the like). The example described in patent document 4 is referred to as comparative example 1.

NI＝77.9℃；Tc<-20℃；Δn＝0.126；Δε＝6.9；ε⊥＝3.8；Vth＝1.79V；γ1＝73mPa·s；K22＝6.8pN；γ1/K22＝10.7GPa·s/N.

The composition of example 1 was prepared using the compound (1-1) in place of the compound (4-8) of comparative example 1.

[ example 1]

NI＝78.3℃；Tc<-20℃；Δn＝0.126；Δε＝6.8；ε⊥＝4.3；Vth＝1.83V；γ1＝62mPa·s；K22＝7.1pN；γ1/K22＝8.7GPa·s/N.

[ example 2]

NI＝105.4℃；Tc<-30℃；Δn＝0.111；Δε＝2.6；γ1＝69mPa·s；K22＝8.3pN；γ1/K22＝8.3GPa·s/N.

[ example 3]

NI＝104.0℃；Tc<-30℃；Δn＝0.111；Δε＝2.5；ε⊥＝4.1；γ1＝65mPa·s；K22＝8.6pN；γ1/K22＝7.6GPa·s/N.

[ example 4]

NI＝75.5℃；Tc<-20℃；Δn＝0.112；Δε＝2.3；ε⊥＝4.0；γ1＝57mPa·s；K22＝6.9pN；γ1/K22＝8.3GPa·s/N.

[ example 5]

NI＝100.0℃；Tc<-40℃；Δn＝0.120；Δε＝2.7；ε⊥＝4.0；γ1＝72mPa·s；K22＝8.0pN；γ1/K22＝9.0GPa·s/N.

[ example 6]

NI＝75.2℃；Tc<-20℃；Δn＝0.114；Δε＝8.5；ε⊥＝4.9；γ1＝60mPa·s；K22＝6.0pN；γ1/K22＝10.0GPa·s/N.

[ example 7]

NI＝103.0℃；Tc<-40℃；Δn＝0.110；Δε＝2.9；ε⊥＝3.7；γ1＝80mPa·s；K22＝8.0pN；γ1/K22＝10.0GPa·s/N.

[ example 8]

NI＝110.2℃；Tc<-30℃；Δn＝0.129；Δε＝2.8；ε⊥＝3.8；γ1＝85mPa·s；K22＝8.8pN；γ1/K22＝9.7GPa·s/N.

[ example 9]

NI＝98.9℃；Tc<-20℃；Δn＝0.108；Δε＝2.5；ε⊥＝3.0；γ1＝54mPa·s；K22＝7.4pN；γ1/K22＝7.3GPa·s/N.

[ example 10]

NI＝105.9℃；Tc<-30℃；Δn＝0.115；Δε＝2.6；ε⊥＝3.8；γ1＝70mPa·s；K22＝7.5pN；γ1/K22＝9.4GPa·s/N.

[ example 11]

NI＝105.2℃；Tc<-30℃；Δn＝0.111；Δε＝2.8；ε⊥＝3.7；γ1＝69mPa·s；K22＝7.0pN；γ1/K22＝9.9GPa·s/N.

Therefore, the following steps are carried out: the dielectric constant (. Epsilon. DELTA. DELTA.1), the rotational viscosity (. Gamma.1), and the ratio of the rotational viscosity to the elastic constant (. Gamma.1/K22) in the minor axis direction of the composition of comparative example 1 were 3.8, 73 mPas, and 10.7GPa s/N, respectively. On the other hand, the compositions of example 1 were 4.3, 62mPa · s and 8.7GPa · s/N, respectively, with a large ∈ ∈ and a small γ 1/K22. Therefore, it was concluded that the composition of the present invention has excellent properties.

[ industrial applicability ]

The liquid crystal composition of the present invention can be used for liquid crystal monitors, liquid crystal televisions, and the like.

Claims

1. A liquid crystal composition containing at least one compound selected from the group consisting of compounds represented by the formula (1) as a component A and at least one compound selected from the group consisting of compounds represented by the formula (2) as a component B, and having positive dielectric anisotropy;

in the formula (1), R ¹ And R ² Is hydrogen, alkyl with carbon number of 1 to 12, alkoxy with carbon number of 1 to 12, alkenyl with carbon number of 2 to 12, alkenyloxy with carbon number of 2 to 12 or alkyl with carbon number of 1 to 12, wherein at least one hydrogen is substituted by fluorine; ring A is 1, 4-cyclohexylene, 1, 4-cyclohexenylene tetrahydropyran-2, 5-diyl, 1, 4-phenylene,At least one 1, 4-phenylene in which hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine, or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine; z ¹ Is a single bond, ethylene, vinylene, methyleneoxy or carbonyloxy; x ¹ And X ² Is fluorine or trifluoromethyl, a is 0, 1 or 2;

in the formula (2), R ³ Is alkyl group with carbon number of 1 to 12, alkoxy group with carbon number of 1 to 12 or alkenyl group with carbon number of 2 to 12; ring B is 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene, 2, 6-difluoro-1, 4-phenylene, pyrimidine-2, 5-diyl, 1, 3-dioxane-2, 5-diyl or tetrahydropyran-2, 5-diyl; z ² Is a single bond, ethylene, vinylene, carbonyloxy or difluoromethyleneoxy; x ³ And X ⁴ Is hydrogen or fluorine; y is ¹ Fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine; b is 1, 2,3 or 4.

2. The liquid crystal composition according to claim 1, comprising at least one compound selected from the group consisting of compounds represented by formulae (1-1) to (1-7) as component a;

in the formulae (1-1) to (1-7), R ¹ And R ² Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted by fluorine.

3. The liquid crystal composition according to claim 1 or 2, wherein the proportion of the component a is in the range of 1 to 20% by mass.

4. The liquid crystal composition according to claim 1 or 2, comprising at least one compound selected from the group consisting of compounds represented by formulae (2-1) to (2-36) as component B;

in the formulae (2-1) to (2-36), R ³ An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms.

5. The liquid crystal composition according to claim 1 or 2, wherein the proportion of the component B is in the range of 10 to 85 mass%.

6. The liquid crystal composition according to claim 1, comprising at least one compound selected from the group consisting of compounds represented by formula (3) as component C;

in the formula (3), R ⁴ And R ⁵ An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine; ring C and ring D are 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene or 2, 5-difluoro-1, 4-phenylene; z ³ Is a single bond, aEthyl, vinylidene, methyleneoxy or carbonyloxy; c is 1, 2 or 3.

7. The liquid crystal composition according to claim 1 or 2, comprising at least one compound selected from the group consisting of compounds represented by formulae (3-1) to (3-15) as component C;

in the formulae (3-1) to (3-15), R ⁴ And R ⁵ Is alkyl group with carbon number of 1 to 12, alkoxy group with carbon number of 1 to 12, alkenyl group with carbon number of 2 to 12 or alkenyl group with carbon number of 2 to 12, wherein at least one hydrogen is substituted by fluorine.

8. The liquid crystal composition according to claim 6, wherein the proportion of the component C is in the range of 10 to 75 mass%.

9. The liquid crystal composition according to claim 1 or 6, comprising at least one compound selected from the group consisting of compounds represented by formula (4) as component D;

in the formula (4), R ⁶ And R ⁷ Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms or alkenyloxy group having 2 to 12 carbon atoms; ring E and ring G are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine, chroman-2, 6-diyl or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine; ring F is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl, 4, 6-difluorodibenzofuran-3, 7-diyl, 4, 6-difluorodibenzothiophene-3, 7-diyl or 1,6, 7-tetrafluoroindan-2, 5-diyl; z ⁴ And Z ⁵ Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; d is 0, 1, 2 or 3; e is 0 or 1; the sum of d and e is 3 or less.

10. The liquid crystal composition according to claim 1 or 6, comprising at least one compound selected from the group consisting of compounds represented by formulae (4-1) to (4-35) as component D;

11. The liquid crystal composition according to claim 9, wherein the proportion of the component D is in the range of 1 to 50% by mass.

12. A liquid crystal display element comprising the liquid crystal composition according to claim 1 or 2.

13. The liquid crystal display element according to claim 12, wherein an operation mode of the liquid crystal display element is a twisted nematic mode, an electrically controlled birefringence mode, an optically compensated bend mode, an in-plane switching mode, a fringe field switching mode, or an electric field induced photoreaction alignment mode, and a driving mode of the liquid crystal display element is an active matrix mode.

14. The liquid crystal composition according to claim 1 or 2, for use in a liquid crystal display element of an in-plane switching mode or a fringe field switching mode.

15. Use of the liquid crystal composition according to claim 1 or 2 for a liquid crystal display element.