TWI851775B - Liquid crystal composition for viewing angle adjustment element, viewing angle adjustment element, display device capable of adjusting viewing angle, and liquid crystal display device - Google Patents

Abstract

The subject of the present invention is to provide a liquid crystal composition for a viewing angle adjustment element, which can obtain a display device having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle. A viewing angle adjustment element having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle and a display device capable of adjusting the viewing angle are provided. A liquid crystal composition, which contains a specific compound as component A and is used in a viewing angle switching layer of a device capable of adjusting the viewing angle, and the composition may further contain a specific compound as component B, and may further contain a specific compound as component C.

Description

Liquid crystal composition for viewing angle adjustment element, viewing angle adjustment element, display device capable of adjusting viewing angle, and liquid crystal display device

The present invention relates to a liquid crystal composition used in a viewing angle switching layer of a device capable of adjusting the viewing angle (a liquid crystal composition for a viewing angle adjusting device), a viewing angle adjusting device containing the composition, and a display device capable of adjusting the viewing angle.

In display devices such as liquid crystal display devices, the position of the viewer is usually not fixed, so the display image is required to be visible from all angles, that is, a wide viewing angle is required. However, on the other hand, there are also cases where, from the perspective of confidentiality or privacy protection, it is required that the display image is visible only to the viewer, that is, only from a limited narrow angle range, and cannot be seen from the surroundings, so as to prevent peeping from the side, that is, a narrow viewing angle is required.

Thus, in recent years, there has been a demand for a display device that can switch between a wide viewing angle and a narrow viewing angle according to the usage conditions, in other words, a display device that can adjust the viewing angle. As a method for adjusting the viewing angle of a display device, for example, a method has been proposed in which a voltage applied to a layer containing a liquid crystal composition (liquid crystal layer) is controlled to control the alignment of liquid crystal molecules, thereby controlling and/or adjusting the viewing angle (Patent Documents 1 to 3). [Prior Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Publication No. 2018-072819 [Patent Document 2] International Publication No. 2008-018212 [Patent Document 3] U.S. Patent Application Publication No. 2009-0021657 Specification

[The problem that the invention wants to solve]

The subject of the present invention is to provide a liquid crystal composition for a viewing angle adjustment element, which can obtain a display device having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle. Another subject of the present invention is to provide a viewing angle adjustment element having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle, and a display device capable of adjusting the viewing angle. [Means for solving the subject]

The present invention relates to a liquid crystal composition for a viewing angle adjusting element, comprising, as component A, at least one compound selected from the group consisting of compounds represented by formula (1). In formula (1), R ^1a and R ^1b are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring A ¹ and Ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Z ¹ is a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; and a ¹ is 1, 2, or 3.

In addition, the present invention relates to a viewing angle adjustment element, and a display device such as a liquid crystal display device capable of adjusting the viewing angle including the viewing angle adjustment element, wherein the viewing angle adjustment element comprises: a viewing angle switching layer including a liquid crystal composition for the viewing angle adjustment element; and a pair of electrodes for applying a voltage to the viewing angle switching layer. [Effect of the invention]

The advantage of the present invention is to provide a liquid crystal composition for a viewing angle adjustment element, which can obtain a display device having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle. Another advantage of the present invention is to provide a viewing angle adjustment element having an excellent viewing angle adjustment function and capable of switching between a wide viewing angle and a narrow viewing angle and a display device capable of adjusting the viewing angle.

The terms used in this specification are as follows. The terms "liquid crystal composition for viewing angle adjustment element" and "liquid crystal composition" are sometimes referred to as "composition" for short. "Liquid crystal display element" is a general term that includes liquid crystal display panels and liquid crystal display modules. "Liquid crystal compound" is a general term for compounds having a nematic phase, a liquid crystal phase like a lamellar phase, and compounds that do not have a liquid crystal phase but are mixed in a composition for the purpose of adjusting the temperature range, viscosity, and dielectric anisotropy-like properties of the nematic phase. The compound has, for example, a six-membered ring like a 1,4-cyclohexyl group or a 1,4-phenyl group, and its molecule (liquid crystal molecule) is rod-like. "Polymerizable compound" is a compound added for the purpose of generating a polymer in a composition. Liquid crystal compounds having an olefin group are not classified as polymerizable in their meaning.

The liquid crystal composition is prepared by mixing a plurality of liquid crystal compounds. Optically active compounds, antioxidants, ultraviolet absorbers, matting agents, dichroic pigments or additives such as polymerizable compounds may be added to the liquid crystal composition as needed. Even when additives are added, the proportion of the liquid crystal compound is expressed by the mass percentage (mass %) based on the mass of the liquid crystal composition without the additive. The proportion of the additive is expressed by the mass percentage (mass %) based on the mass of the liquid crystal composition without the additive. That is, the proportion of the liquid crystal compound or the additive is calculated based on the total mass of the liquid crystal compound. Sometimes parts per million (ppm) is used. The proportion of the polymerization initiator and the polymerization inhibitor is expressed exceptionally based on the mass of the polymerizable compound.

Sometimes, the "upper limit temperature of the nematic phase" is referred to as the "upper limit temperature". Sometimes, the "lower limit temperature of the nematic phase" is referred to as the "lower limit temperature". Regarding the expression "increasing the dielectric anisotropy", in the case of a composition with positive dielectric anisotropy, it means that its value increases positively, and in the case of a composition with negative dielectric anisotropy, it means that its value increases negatively. "High voltage retention rate" means that the element has a high voltage retention rate not only at room temperature but also at a temperature close to the upper limit temperature in the initial stage, and that after long-term use, it has a high voltage retention rate not only at room temperature but also at a temperature close to the upper limit temperature. Sometimes, the characteristics of a composition or element are studied through a time change test.

The compound (1z) is used as an example for explanation. In formula (1z), 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-like ring. When the subscript 'x' is 2, there are two rings α. The two groups represented by the two rings α may be the same or different. The above rule applies to any two rings α when the subscript 'x' is greater than 2. The above rule also applies to other symbols such as the bonding group Z. The slash that crosses one side of the ring β indicates that any hydrogen on the ring β can be substituted by a substituent (-Sp-P). The subscript 'y' indicates the number of substituents replaced. When the subscript 'y' is 0, there is no such substitution. When the subscript 'y' is 2 or more, there are multiple substituents (-Sp-P) on ring β. In this case, the rule of "may be the same or different" also applies. Furthermore, the above rule also applies to the case where symbols such as Ra and Rb are used in multiple compounds.

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

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

The expression "at least one 'A'" means that the number of 'A' is arbitrary. The expression "at least one 'A' may be substituted by 'B'" means that when the number of 'A' is one, the position of 'A' is arbitrary, and when the number of 'A' is two or more, the positions can also be selected without limitation. The expression "at least one -CH ₂ - may be substituted by -O-" is sometimes used. In such a case, -CH ₂ -CH ₂ -CH ₂ - may be converted to -O-CH ₂ -O- by replacing a non-adjacent -CH ₂ - with -O-. However, there is no case where an adjacent -CH ₂ - is substituted by -O-. The reason is that -OO-CH ₂ - (peroxide) is generated in such substitution.

The alkyl group of the liquid crystal compound is linear or branched, and does not include cyclic alkyl groups. Generally, linear alkyl groups are preferred over branched alkyl groups. This is also true for terminal groups such as alkoxy and alkenyl groups. Regarding the stereo configuration associated with 1,4-cyclohexylene, in order to increase the upper temperature limit, the trans configuration is generally preferred over the cis configuration. Since 2-fluoro-1,4-phenylene is asymmetric, there are left-facing (L) and right-facing (R) configurations. The same is true for divalent groups such as tetrahydropyran-2,5-diyl and for bonding groups such as carbonyloxy (-COO- or -OCO-).

The present invention includes the following items, etc.

Item 1. A liquid crystal composition for a viewing angle adjusting element, comprising as component A at least one compound selected from the group consisting of compounds represented by formula (1), In formula (1), R ^1a and R ^1b are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring A ¹ and Ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Z ¹ is a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; and a ¹ is 1, 2, or 3.

Item 2. The liquid crystal composition for a viewing angle adjusting element according to Item 1, comprising as component A at least one compound selected from the group consisting of compounds represented by formula (1-1) to formula (1-14), In formula (1-1) to formula (1-14), R ^1a and R ^1b are alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyl having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine.

Item 3. The liquid crystal composition for a viewing angle adjusting element according to Item 2, comprising as component A at least one compound selected from the group consisting of compounds represented by Formula (1-3), Formula (1-6), Formula (1-7), Formula (1-8), Formula (1-9), Formula (1-12) and Formula (1-13).

Item 4. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 3, wherein the ratio of component A is in the range of 5 mass % to 90 mass %.

Item 5. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 4, comprising as component B at least one compound selected from the group consisting of compounds represented by formula (2), In formula (2), ^R2 is 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; Ring ^A2 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; ^Z2 is a single bond, ethylene, ethenylene, carbonyloxy, or difluoromethyleneoxy; ^X2a and ^X2b are hydrogen or fluorine; Y ^a2 is fluorine, chlorine, cyano, 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; ^a2 is 1, 2, 3 or 4.

Item 6. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 5, comprising as component B at least one compound selected from the group consisting of compounds represented by formula (2-1) to formula (2-39), In formula (2-1) to formula (2-39), R ² is 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; and X ^2a and X ^2b are hydrogen or fluorine.

Item 7. The liquid crystal composition for a viewing angle adjusting element according to Item 5 or Item 6, wherein the ratio of component B is in the range of 5 mass % to 90 mass %.

Item 8. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 7, comprising as component C at least one compound selected from the group consisting of compounds represented by formula (3), In formula (3), R ^3a and R ^3b are hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms; Ring A ³ and Ring C ³ are 1,4-cyclohexylene, 1,4-cyclohexenyl, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring B ^Z3 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 1,1,6,7-tetrafluoroindan-2,5-diyl; ^Z3a and ^Z3b are a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; ^a3 is 0, 1, 2, or 3, ^b3 is 0 or 1; and the sum of ^a3 and ^b3 is 3 or less.

Item 9. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 8, comprising as component C at least one compound selected from the group consisting of compounds represented by formula (3-1) to formula (3-35), In formula (3-1) to formula (3-35), R ^3a and R ^3b are hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms.

Item 10. The liquid crystal composition for a viewing angle adjusting element according to Item 8 or Item 9, wherein the ratio of component C is in a range of 5 mass % to 90 mass % based on the mass of the liquid crystal composition.

Item 11. The liquid crystal composition for a viewing angle adjusting element according to any one of Items 1 to 10, wherein the optical anisotropy at a wavelength of 589 nm (measured at 25° C.) is in the range of 0.15 to 0.25.

Item 12. A viewing angle adjustment element, comprising: a viewing angle switching layer; and a pair of electrodes for applying a voltage to the viewing angle switching layer, wherein the viewing angle switching layer comprises a liquid crystal composition for a viewing angle adjustment element, wherein the liquid crystal composition for a viewing angle adjustment element comprises at least one compound selected from the compounds represented by formula (1) as component A, In formula (1), R ^1a and R ^1b are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring A ¹ and Ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Z ¹ is a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; and a ¹ is 1, 2, or 3.

Item 13. A viewing angle adjustment element as described in Item 12, wherein when the optical anisotropy (measured at 25°C) of the liquid crystal composition used for the viewing angle adjustment element at a wavelength of 589 nm is set to Δn and the thickness of the viewing angle switching layer is set to d, the product of Δn and d (Δn×d) is greater than 700 nm.

Item 14. A display device capable of adjusting the viewing angle, comprising a viewing angle adjustment element as described in Item 12 or Item 13.

Item 15. A liquid crystal display device capable of adjusting the viewing angle, comprising a viewing angle adjustment element as described in Item 12 or Item 13.

Item 16. The liquid crystal composition for a viewing angle adjusting element as described in any one of Items 1 to 11, which does not contain a tolan derivative.

<Liquid crystal composition for viewing angle adjustment element> The liquid crystal composition for viewing angle adjustment element of the present invention is described in the following order. First, the composition is described. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or the viewing angle adjustment element are described. Third, the combination of the component compounds in the composition, the preferred ratio and the basis thereof are described. Fourth, the preferred form of the component compounds is described. Fifth, the preferred component compounds are shown. Sixth, the additives and other component compounds that can be added to the composition are described. Seventh, the synthesis method of the component compounds is described. Eighth, the characteristics of the composition required or suitable for use in the viewing angle switching layer of the viewing angle adjustment element are described.

First, the composition of the composition is described. The liquid crystal composition for viewing angle adjustment element of the present invention contains a plurality of liquid crystal compounds, and contains at least one liquid crystal compound selected from compound (1). The composition may further contain additives. The additives are optically active compounds, antioxidants, ultraviolet absorbers, matting agents, pigments, defoaming agents, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, etc.

From the perspective of liquid crystal compounds, the composition is classified into composition (a) and composition (b). In addition to the liquid crystal compound selected from compound (1), compound (2) and compound (3), composition (a) may also contain other liquid crystal compounds (component compounds), and may further contain additives, etc. (wherein, composition (a) contains at least one liquid crystal compound selected from compound (1) as an essential component). "Other liquid crystal compounds" are liquid crystal compounds different from compound (1), compound (2) and compound (3). Such compounds are mixed in the composition for the purpose of further adjusting the characteristics.

The composition (b) substantially comprises only a liquid crystal compound selected from the group consisting of the compound (1), the compound (2) and the compound (3) (wherein the composition (b) also contains at least one liquid crystal compound selected from the compound (1) as an essential component). "Substantially" means that the composition (b) may contain additives but does not contain other liquid crystal compounds. The other liquid crystal compounds are not particularly limited and any known liquid crystal compounds may be used.

Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or the viewing angle adjustment element are described. Based on the effects of the present invention, the main characteristics of the component compounds are summarized in Table 2. In the symbols in Table 2, L means large or high, M means medium, and S means small or low. The symbols L, M, and S are classified based on qualitative comparison between the component compounds, and 0 (zero) means less than S.

Table 2. Properties of liquid crystal compounds Compound Compound (1) Compound (2) Compound (3) Upper limit temperature S～L S～L S～L Viscosity S～M M～L M～L Optical anisotropy S～L M～L M～L Dielectric anisotropy 0 S～L M～L ^{1 ）} Specific resistance L L L 1) The dielectric anisotropy is negative, and the sign indicates the magnitude of the absolute value.

The main characteristics and effects of the component compounds are as follows. Compound (1) has appropriate optical anisotropy, viscosity, specific resistivity and other characteristics. By using compound (1), a liquid crystal composition that can obtain a viewing angle adjustment element with good characteristics can be prepared. Compound (2) has a large positive dielectric anisotropy and at least one of the appropriate optical anisotropy, viscosity, specific resistivity and other characteristics. It can be suitably used to prepare a liquid crystal composition for a viewing angle adjustment element with positive dielectric anisotropy. Compound (3) has a large negative dielectric anisotropy and at least one of the appropriate optical anisotropy, viscosity, specific resistivity and other characteristics. It can be suitably used to prepare a liquid crystal composition for a viewing angle adjustment element with negative dielectric anisotropy. When the compound (3) is used in a liquid crystal composition having positive dielectric anisotropy, the dielectric constant in the perpendicular direction can be increased.

Third, the combination of the component compounds in the composition, the preferred ratio and the basis thereof are described. The preferred combination of the component compounds in the composition is compound (1) + compound (2), compound (1) + compound (3), or compound (1) + compound (2) + compound (3). A further preferred combination is compound (1) + compound (2), or compound (1) + compound (3).

In order to increase the optical anisotropy or reduce the viscosity, the preferred ratio of compound (1) [component A] is about 5 mass % or more, and in order to increase the dielectric anisotropy, the preferred ratio of compound (1) [component (A)] is about 90 mass % or less. A further preferred ratio is in the range of about 10 mass % to about 80 mass %. A particularly preferred ratio is in the range of about 30 mass % to about 80 mass %.

In order to improve the dielectric anisotropy, the preferred ratio of compound (2) [component B] is about 5 mass % or more, and in order to reduce the minimum temperature, the preferred ratio of compound (2) [component B] is about 90 mass % or less. A further preferred ratio is in the range of about 10 mass % to about 85 mass %. A particularly preferred ratio is in the range of about 15 mass % to about 80 mass %.

In order to increase the dielectric anisotropy or increase the dielectric constant in the perpendicular direction, the preferred ratio of compound (3) [component C] is about 5 mass % or more, and in order to lower the minimum temperature, the preferred ratio of compound (3) [component C] is about 90 mass % or less. A further preferred ratio is in the range of about 5 mass % to about 80 mass %. A particularly preferred ratio is in the range of about 10 mass % to about 70 mass %.

Fourth, the preferred form of the component compound is described. In formula (1), R ^1a and R ^1b are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine. In order to reduce the viscosity, preferably R ^1a or R ^1b is an alkenyl group having 2 to 12 carbon atoms, and in order to improve the stability, preferably R ^1a or R ^1b is an alkyl group having 1 to 12 carbon atoms. In formula (2), R ² is an alkyl group having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms. In order to improve the stability, preferably R ² is an alkyl group having 1 to 12 carbon atoms. In formula (3), R ^3a and R ^3b are hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms. In order to improve stability, R ^3a is preferably an alkyl group having 1 to 12 carbon atoms, and in order to reduce viscosity, R ^{3a is} preferably an alkenyl group having 2 to 12 carbon atoms. In order to improve dielectric anisotropy, R ^3b is preferably an alkoxy group having 1 to 12 carbon atoms.

Preferred alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl. In order to reduce the viscosity, further preferred alkyl groups are methyl, ethyl, propyl, butyl, or pentyl.

Preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, or heptyloxy. In order to reduce the viscosity, further preferred alkoxy groups 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. In order to reduce viscosity, further preferred alkenyl groups are vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl. The preferred stereo configuration of -CH=CH- in these alkenyl groups depends on the position of the double bond. In terms of reducing viscosity, the trans configuration is preferred in alkenyl groups such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl, and 3-hexenyl. In alkenyl groups such as 2-butenyl, 2-pentenyl and 2-hexenyl, the cis configuration is preferred.

Preferred alkenyloxy groups are vinyloxy, allyloxy, 3-butenyloxy, 3-pentenyloxy, or 4-pentenyloxy. In order to reduce the viscosity, further preferred alkenyloxy groups are allyloxy or 3-butenyloxy.

Preferred examples of the alkenyl group in which at least one hydrogen is substituted with fluorine or chlorine are 2,2-difluorovinyl, 3,3-difluoro-2-propenyl, 4,4-difluoro-3-butenyl, 5,5-difluoro-4-pentenyl, or 6,6-difluoro-5-hexenyl. Further preferred examples are 2,2-difluorovinyl or 4,4-difluoro-3-butenyl in order to reduce the viscosity.

In formula (1), ring A ¹ and ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl. In order to improve the optical anisotropy, ring A ¹ or ring B ¹ is preferably 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene. In a certain embodiment, preferably at least two of ring ^A1 and ring ^B1 , more preferably two or three of ring ^A1 and ring ^B1 are 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene. Particularly preferably, at least two of ring ^A1 and ring ^B1 , more preferably two or three of ring ^A1 and ring ^B1 are 1,4-phenylene or 2-fluoro-1,4-phenylene. By using a compound represented by formula (1) in which at least two of ring ^A1 and ring ^B1 , more preferably two or three of ring ^A1 and ring ^B1 are 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,5-difluoro-1,4-phenylene, a composition having a large optical anisotropy can be prepared, and there is a tendency to easily prepare a composition having good other properties.

In formula (2), ring ^A2 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. In order to improve the optical anisotropy, the preferred ring ^A2 is 1,4-phenylene or 2-fluoro-1,4-phenylene, and in order to improve the dielectric anisotropy, the preferred ring ^A2 is 2,6-difluoro-1,4-phenylene or 1,3-dioxane-2,5-diyl. The tetrahydropyran-2,5-diyl in ring ^A2 is or , preferably .

In formula (3), ring ^A3 and ring ^C3 are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine. Preferred examples of "1,4-phenylene in which at least one hydrogen atom is substituted with fluorine or chlorine" are 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene or 2-chloro-3-fluoro-1,4-phenylene. In order to reduce the viscosity, the preferred ring A ³ or ring C ³ is 1,4-cyclohexylene. In order to increase the upper limit temperature, the preferred ring A ³ or ring C ³ is tetrahydropyran-2,5-diyl. In order to increase the optical anisotropy, the preferred ring A ³ or ring C ³ is 1,4-phenylene. The tetrahydropyran-2,5-diyl in ring A ³ and ring C ³ is or , preferably .

Ring ^B3 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 (FLF4), 4,6-difluorodibenzofuran-3,7-diyl (DBFF2), 4,6-difluorodibenzothiophene-3,7-diyl (DBTF2), or 1,1,6,7-tetrafluoroindan-2,5-diyl (InF4). In order to improve the dielectric anisotropy, the preferred ring B ³ is 2,3-difluoro-1,4-phenylene.

In formula (1), ^Z1 is a single bond, an ethyl group, a vinyl group, a methyleneoxy group, or a carbonyloxy group. In order to reduce the viscosity, ^Z1 is preferably a single bond. In formula (2), ^Z2 is a single bond, an ethyl group, a vinyl group, a carbonyloxy group, or a difluoromethyleneoxy group. In order to reduce the viscosity, ^Z2 is preferably a single bond, and in order to increase the dielectric anisotropy, ^Z2 is preferably a difluoromethyleneoxy group. In formula (3), ^Z3a and ^Z3b are a single bond, an ethyl group, a vinyl group, a methyleneoxy group, or a carbonyloxy group. In order to reduce the viscosity, Z ^3a or Z ^3b is preferably a single bond, in order to reduce the minimum temperature, Z ^3a or Z ^3b is preferably an ethylene group, and in order to increase the dielectric anisotropy, Z ^3a or Z ^3b is preferably a methyleneoxy group.

Bivalent groups such as methyleneoxy groups are not symmetrical. In methyleneoxy groups, -CH ₂ O- is preferred to -OCH ₂ -. In carbonyloxy groups, -COO- is preferred to -OCO-.

In formula (2), X ^2a and X ^2b are hydrogen or fluorine. In order to improve the dielectric anisotropy, preferably X ^2a or X ^2b is fluorine.

Y ² is fluorine, chlorine, cyano, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine. From the viewpoint of dielectric anisotropy, Y ² is preferably fluorine or cyano. From the viewpoint of light stability, fluorine is superior to cyano. From the viewpoint of dielectric anisotropy, cyano is preferred. With respect to the compound of formula (2) in which Y ² is cyano, it is easy to achieve a large dielectric anisotropy by using it, and there is a case where it is more suitable for preparing a composition having a large optical anisotropy by combining it with other compounds.

In formula (1), ^a1 is 1, 2 or 3. In order to reduce the viscosity, ^a1 is preferably 1, and in order to increase the upper limit temperature, ^a1 is preferably 2 or 3. In formula (2), ^a2 is 1, 2, 3 or 4. In order to increase the dielectric anisotropy, ^a2 is preferably 2 or 3. In formula (3), ^a3 is 0, 1, 2 or 3, ^b3 is 0 or 1, and the sum of ^a3 and ^b3 is 3 or less. In order to reduce the viscosity, ^a3 is preferably 1, and in order to increase the upper limit temperature, ^a3 is preferably 2 or 3. In order to reduce the viscosity, ^b3 is preferably 0, and in order to reduce the lower limit temperature, ^b3 is preferably 1.

Fifth, preferred component compounds are shown. Preferred compound (1) [Component A] is compound (1-1) to compound (1-14) described in item 2. Among these compounds, at least one of the components A is preferably compound (1-3), compound (1-6), compound (1-7), compound (1-8), compound (1-9), compound (1-12), or compound (1-13). In one embodiment, at least two of the components A are preferably compounds selected from compound (1-3), compound (1-6), compound (1-7), compound (1-8), compound (1-9), compound (1-12), and compound (1-13). Preferably, at least two of the components A are a combination of compound (1-3) and compound (1-6), compound (1-3) and compound (1-8), compound (1-3) and compound (1-13), compound (1-6) and compound (1-8), compound (1-6) and compound (1-13), or compound (1-8) and compound (1-13).

The total amount of the compound (1-3), the compound (1-6), the compound (1-7), the compound (1-8), the compound (1-9), the compound (1-12) and the compound (1-13) is preferably 15% by mass or more based on the mass of the liquid crystal composition. The total amount of the compound (1-3), the compound (1-6), the compound (1-7), the compound (1-8), the compound (1-9), the compound (1-12) and the compound (1-13) is particularly preferably 20% by mass or more based on the mass of the liquid crystal composition. In addition, the total amount of the compound (1-3), the compound (1-6), the compound (1-7), the compound (1-8), the compound (1-9), the compound (1-12) and the compound (1-13) is preferably 50% by mass or more based on the total mass of component A.

Preferred compound (2) [Component B] is compound (2-1) to compound (2-39) described in item 6. Among these compounds, preferably at least one of component B is compound (2-8), compound (2-15), compound (2-18), compound (2-19), compound (2-20), compound (2-23), compound (2-24), compound (2-29), or compound (2-30). In one embodiment, preferably at least two of component B are a combination of compound (2-8) and compound (2-15), compound (2-15 and compound (2-18), compound (2-15 and compound (2-19), compound (2-15) and compound (2-29), compound (2-15) and compound (2-30), compound (2-18) and compound (2-29), or compound (2-18) and compound (2-30).

Preferred compound (3) [Component C] is compound (3-1) to compound (3-35) described in item 9. Among these compounds, at least one of which is preferably component C is compound (3-1), compound (3-3), compound (3-6), compound (3-8), compound (3-10), compound (3-14), compound (3-16), compound (3-18), compound (3-19), or compound (3-34). In one embodiment, it is preferred that at least two of the components C are a combination of compound (3-1) and compound (3-8), compound (3-1) and compound (3-14), compound (3-3) and compound (3-8), compound (3-3) and compound (3-14), compound (3-3) and compound (3-16), compound (3-6) and compound (3-8), compound (3-6) and compound (3-10), or compound (3-6) and compound (3-14).

Sixth, the additives and other component compounds that can be added to the composition are described. Such additives are optically active compounds, antioxidants, ultraviolet absorbers, delustering agents, dichroic pigments, defoaming agents, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, etc. Furthermore, other component compounds will be described later.

In order to induce a helical structure of liquid crystal molecules to impart a torsion angle, an optically active compound may be added to the composition. Examples of such compounds include compounds (5-1) to (5-5). The preferred ratio of the optically active compound is about 5% by mass or less. A further preferred ratio is in the range of about 0.01% by mass to about 2% by mass.

In order to prevent the decrease in specific resistance due to heating in the atmosphere, or to maintain a high voltage holding rate not only at room temperature but also at a temperature close to the upper limit temperature after the viewing angle adjustment element is used for a long time, an antioxidant may be further added to the composition. Examples of the antioxidant include compounds (6-1) to (6-3).

Compound (6-2) has low volatility and is effective in maintaining a high voltage retention rate not only at room temperature but also at a temperature close to the upper limit temperature after the viewing angle adjustment element is used for a long time. In order to obtain the above effect, the preferred ratio of the antioxidant is about 50 ppm or more, and in order not to lower the upper limit temperature or to not increase the lower limit temperature, the preferred ratio of the antioxidant is about 600 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 300 ppm.

Preferred examples of ultraviolet absorbers are benzophenone derivatives, benzoate derivatives, triazole derivatives, and the like. In addition, sterically hindered amine-like light stabilizers are also preferred. Preferred examples of light stabilizers are compounds (7-1) to (7-16), and the like. In order to obtain the above-mentioned effect, the preferred ratio of these ultraviolet absorbers or light stabilizers is about 50 ppm or more, and in order not to lower the upper limit temperature or to not increase the lower limit temperature, the preferred ratio of these ultraviolet absorbers or light stabilizers is about 10000 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 10000 ppm.

The matting agent is a compound that prevents the decomposition of the liquid crystal compound by receiving light energy absorbed by the liquid crystal compound and converting it into heat energy. Preferred examples of the matting agent are compounds (8-1) to (8-7) and the like. In order to obtain the above-mentioned effect, the preferred ratio of the matting agent is about 50 ppm or more, and in order not to increase the lower limit temperature, the preferred ratio of the matting agent is about 20000 ppm or less. A further preferred ratio is in the range of about 100 ppm to about 10000 ppm.

Examples of dichroic pigments are benzothiadiazoles, diketopyrrolopyrroles, azo compounds, azomethine compounds, methine compounds, anthraquinones, merocyanines, naphthoquinones, tetrazines, pyrromethenes, and perylenes or rylenes such as terrylenes. Preferred dichroic pigments are benzothiadiazoles, diketopyrrolopyrroles, azo compounds, anthraquinones, and rylenes. Particularly preferred dichroic pigments are benzothiadiazoles, diketopyrrolopyrroles, azo compounds, and rylenes. For example, benzothiadiazoles refer to dichroic dyes having a benzothiadiazole ring.

Examples of dichroic dyes include compounds (9-1) to (9-110).

Examples of commercially available dichroic pigments include G-207, G-241, G-305, G-470, G-471, G-472, LSB-278, LSB-335, NKX-1366, NKX-3538, NKX-3540, NKX-3622, NKX-3739, NKX-3742, NKX-3773, NKX-4010, and NKX-4033 manufactured by Nagase Sangyo; and S-428, SI-426, SI-486, M-412, and M-483 manufactured by Mitsui Chemicals Fine.

An example of the polymerizable compound is a compound represented by formula (10). In formula (10), Ring A ¹⁰ and Ring C ¹⁰ are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1,3-dioxane-2-yl, pyrimidin-2-yl, or pyridin-2-yl, and at least one hydrogen in these rings may be substituted by fluorine, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by fluorine; Ring B ^Z10a and Z10b are 1,4-cyclohexylene, 1,4-cyclohexenyl, 1,4-phenylene, naphthalene-1,2-diyl, naphthalene-1,3-diyl, naphthalene-1,4-diyl, naphthalene-1,5-diyl, naphthalene-1,6-diyl, naphthalene-1,7-diyl, naphthalene-1,8-diyl, naphthalene-2,3-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl, or pyridine-2,5-diyl, and at least one hydrogen in these rings may be substituted by fluorine, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted by ^fluorine ; ^P10a , P10b, and P10c are polymerizable groups; Sp10a, Sp10b _, and Sp10c are single bonds or alkylene groups having 1 to 10 carbon atoms, in which at least one _-CH2- may be substituted by -O-, -CO-, -COO-, or -OCO-, at least one _-CH2CH2- may be substituted by -CH=CH-, -C( _CH3 )=CH-, -CH=C( _CH3 )-, or -C( _CH3 )=C( _CH3 )-, and at least one hydrogen in these groups may be substituted by fluorine; ^P10a , ^P10b , and ^P10c are polymerizable groups; ^Sp10a , ^Sp10b , and ^Sp10c are single bonds or alkylene groups having 1 to 10 carbon atoms, in which at least one -CH2- may be substituted by -O-, -COO-, or -OCO-, at least one _-CH2CH2- may be substituted by -O-, -COO-, or _-OCO- , at least one _-CH2CH2 - may be substituted by -CH=CH- or -C≡C-, and at least one hydrogen in these groups may be substituted by fluorine; ^a10 is 0, 1 or 2; ^b10 , ^c10 , and ^d10 are 0, 1, 2, 3 or 4, and the sum of ^b10 , ^c10 , and ^d10 is 1 or more. In formula (10), preferred ^P10a , ^P10b , and ^P10c are polymerizable groups represented by the following formulas (P-1) to (P-3). In formula (P-1) to formula (P-3), M ¹ , M ² and M ³ are hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen atom is substituted with fluorine.

Preferred examples of the polymerizable compound include compounds represented by formula (10-1) to formula (10-29).

In formula (10-1) to formula (10-29), ^P10a , ^P10b , and ^P10c are groups selected from the polymerizable groups represented by formula (P-1) to formula (P-3), wherein ^M1 , ^M2 , and ^M3 are hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine; Sp ^10a , Sp ^10b , and Sp ^10c are single bonds or alkylene groups having 1 to 10 carbon atoms, wherein at least one -CH ₂ - in the alkylene group may be substituted by -O-, -COO-, or -OCO-, and at least one -CH ₂ CH ₂ - may be substituted by -CH=CH- or -C≡C-. In these groups, at least one hydrogen may be substituted by fluorine.

Examples of other component compounds include compounds represented by formula (11). In formula (11), R ^11a and ^{R 11b} are alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, or alkenyl groups having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring A ¹¹ is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Ring B ¹¹ and Ring C ¹¹ are 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z ^11a is a single bond, ethylene, ethenylene, ethynylene, methyleneoxy, or carbonyloxy; and a ¹¹ is 0, 1, or 2.

Preferred examples of formula (11) are formula (11-1) to formula (11-3). In formula (11-1) to formula (11-3), R ^11a and R ^11b are alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyl having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine.

Compounds having a structure in which two benzene rings are bonded via an ethynylene group, such as the compound represented by formula (11), are called tolan derivatives. From the viewpoint of improving optical anisotropy, tolan derivatives are preferred. On the other hand, tolan derivatives tend to reduce voltage holding ratio. Therefore, in particular, in order to prepare a device having a high voltage holding ratio, it is preferred not tolan derivatives.

It should be noted that the component compound (liquid crystal compound) that the composition may contain is not limited to the compound represented by the above formula (11).

Seventh, the synthesis method of the component compounds is described. These compounds can be synthesized using known methods. The synthesis method is illustrated. Compound (1-1) can be synthesized using the method described in Japanese Patent Laid-Open No. 59-176221. Compound (2-4) can be synthesized using the method described in Japanese Patent Laid-Open No. 10-204016. Compound (3-1) can be synthesized using the method described in Japanese Patent Laid-Open No. 2000-053602. Antioxidants are already commercially available. For example, compound (6-1) can be obtained from Aldrich (Sigma-Aldrich Corporation). Compound (6-2) and the like can be synthesized using the method described in the specification of U.S. Patent No. 3,660,505.

Compounds other than those described above can be synthesized by methods described in the following books: Organic Syntheses (John Wiley & Sons, Inc.), Organic Reactions (John Wiley & Sons, Inc.), Comprehensive Organic Synthesis (Pergamon Press), New Experimental Chemistry Lectures (Maruzen), etc. The composition is prepared from the compounds obtained in the above manner by a known method. For example, the composition can be prepared by mixing the component compounds and then dissolving them in each other by heating.

Eighth, the characteristics of the composition required or suitable for use in the viewing angle switching layer of the viewing angle adjustment element are explained.

In order to achieve an excellent viewing angle adjustment function, the optical anisotropy of the composition is usually preferably large. Specifically, the optical anisotropy of the composition at a wavelength of 589 nm (measured at 25°C) is preferably 0.15 or more, and more preferably 0.18 or more. In a certain embodiment, a larger optical anisotropy is preferred, for example, the optical anisotropy of the composition at a wavelength of 589 nm (measured at 25°C) is preferably 0.19 or more. On the other hand, from the viewpoint of other characteristics required for the viewing angle adjustment element, or the balance with these characteristics, the optical anisotropy of the composition at a wavelength of 589 nm (measured at 25°C) is usually preferably 0.25 or less.

In order to obtain a viewing angle adjustment element having good characteristics, the absolute value of the dielectric anisotropy (measured at 25° C.) of the composition is preferably 2.0 or more. Furthermore, the composition may have positive dielectric anisotropy or negative dielectric anisotropy.

The viscosity of the composition is related to the time required for the wide viewing angle and narrow viewing angle of the viewing angle adjustment element to switch (response time). The shorter the time required for switching between the wide viewing angle and the narrow viewing angle, the better. Therefore, the smaller the viscosity of the composition, the better.

The temperature range of the nematic phase is related to the temperature range of the viewing angle adjustment element and the display device capable of adjusting the viewing angle including the element. Generally, the usable temperature range of the display device is preferably wide, and therefore, the temperature range of the nematic phase is preferably wide. When applied to a liquid crystal display device, generally, the upper limit temperature of the nematic phase is preferably above about 70°C, and the lower limit temperature of the nematic phase is preferably below about -10°C.

The specific resistance of the composition is related to the voltage holding ratio of the viewing angle adjustment element. Generally, the voltage holding ratio of the viewing angle adjustment element is preferably large, and the specific resistance of the composition is also preferably large. A composition having a large specific resistance in the initial stage is preferred. In addition, a composition having a large specific resistance even after long-term use is preferred.

In addition, since the life of the viewing angle adjustment element is prolonged, the stability of the composition to light or heat is preferably high.

The liquid crystal composition for viewing angle adjustment element of the present invention is different from "Polymer Dispersed Liquid Crystal (PDLC)" used in the conventional switching layer that can electronically switch between a transparent state and a scattering state. In addition, polymer dispersed liquid crystal is a liquid crystal in which a liquid crystal composition is dispersed in a polymer obtained by polymerizing a polymerizable compound, but if it is not in this form (liquid crystal in which a liquid crystal composition is dispersed in a polymer), the liquid crystal composition for viewing angle adjustment element of the present invention may also contain a polymerizable compound or a polymer obtained by polymerizing a polymerizable compound.

<Viewing angle adjustment element and display device capable of adjusting viewing angle> The viewing angle adjustment element of the present invention comprises: a viewing angle switching layer, comprising a liquid crystal composition containing at least one liquid crystal compound selected from compound (1); and a pair of electrodes for applying a voltage to the viewing angle switching layer. That is, in the viewing angle adjustment element of the present invention, the viewing angle switching layer comprises the liquid crystal composition for the viewing angle adjustment element of the present invention, and the preferred composition is also the same as described above.

In the viewing angle adjustment element of the present invention, from the viewpoint of excellent viewing angle adjustment function, generally, when the optical anisotropy (measured at 25°C) of the liquid crystal composition for the viewing angle adjustment element at a wavelength of 589 nm is set to Δn and the thickness of the viewing angle switching layer is set to d, the product of Δn and d (Δn×d) is preferably large. Specifically, the product of Δn and d is preferably greater than 700 nm. In a certain embodiment, the product of Δn and d is preferably greater than 720 nm. On the other hand, the upper limit of the product of Δn and d is not particularly limited, and generally, it is preferably less than about 1300 nm, and particularly preferably less than 900 nm. Furthermore, there are many cases where the display device is required to be thinner, and generally, the thickness d of the viewing angle switching layer is preferably smaller.

The display device of the present invention is a display device capable of adjusting the viewing angle and comprising the viewing angle adjusting element of the present invention. The display element combined with the viewing angle adjusting element of the present invention is not particularly limited, and can be, for example, a liquid crystal display element or an organic electroluminescence (EL) display element.

The liquid crystal display device of the present invention is a liquid crystal display device capable of adjusting the viewing angle and comprising the viewing angle adjusting element of the present invention. The combined liquid crystal display element is also not particularly limited. In the liquid crystal display element, the classification based on the operation mode of the liquid crystal molecules is 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 other modes. Based on the driving method of the element, it is classified into passive matrix (PM) and active matrix (AM). PM is classified into static, multiplex, etc., and AM is classified into thin film transistor (TFT), metal insulator metal (MIM), etc. TFT is classified into amorphous silicon and polycrystalline silicon, and the latter is classified into high temperature type and low temperature type according to the manufacturing steps. Based on the light source, it is classified into reflective type using natural light, transmissive type using backlight, and semi-transmissive type using both natural light and backlight. In the liquid crystal display device of the present invention, liquid crystal display elements of any of these modes and driving methods can also be appropriately used. A polymer sustained alignment (PSA) type liquid crystal display element may also be used appropriately. Furthermore, the liquid crystal composition used in the liquid crystal display element is not particularly limited and may be appropriately selected according to the required characteristics and the like.

Next, a preferred embodiment of the display device of the present invention will be described with reference to the accompanying drawings. Furthermore, the situation shown below is an example and is not limited thereto. In the case of a display device in which the display element combined with the viewing angle adjustment element of the present invention is an organic EL display element, no backlight is required. The display device of the present invention is characterized in that it includes a viewing angle adjustment element (the viewing angle adjustment element of the present invention), and the viewing angle adjustment element includes a viewing angle switching layer including a liquid crystal composition for the viewing angle adjustment element of the present invention, and other elements constituting the display device including the display element, or their structures are not particularly limited. The viewing angle adjustment element of the present invention is also characterized in that it includes a viewing angle switching layer including a liquid crystal composition for the viewing angle adjustment element of the present invention, and other elements constituting the viewing angle adjustment element, or their structures are not particularly limited. Furthermore, the materials constituting the elements of the display device or the viewing angle adjustment element, such as the transparent electrode, the light-transmitting substrate, the alignment film, and the polarizing plate, are not particularly limited, and any commonly used known materials may be used.

Fig. 1 is a schematic cross-sectional view showing the structure of an example of a liquid crystal display device according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the liquid crystal display device shown in Fig. 1. The liquid crystal display device shown in Figs. 1 and 2 is an example of a liquid crystal display device using a liquid crystal composition having positive dielectric anisotropy in a viewing angle switching layer.

The liquid crystal display device 1 shown in FIG. 1 and FIG. 2 includes: a viewing angle adjustment element 10 for switching the viewing angle characteristics of the liquid crystal display device 1; a liquid crystal display element 20; a backlight 30; a first polarizer 41 disposed between the backlight 30 and the viewing angle adjustment element 10; a second polarizer 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20; and a third polarizer 43 disposed on the liquid crystal display element 20. In the description of FIG. 1 and FIG. 2 , light incident on the liquid crystal display element 20 passes through the polarizer 43.

The viewing angle adjustment element 10 includes: a first light-transmitting substrate 13a having a first transparent electrode 12a on the surface; a second light-transmitting substrate 13b having a second transparent electrode 12b on the surface; and a viewing angle switching layer 11, which is sandwiched by a pair of transparent electrodes 12a and a transparent electrode 12b, and the pair of transparent electrodes 12a and a transparent electrode 12b can apply a voltage to the viewing angle switching layer 11. The transmission axis 41a of the first polarizing plate 41 disposed between the backlight 30 and the viewing angle adjustment element 10 and the transmission axis 42a of the second polarizing plate 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20 are substantially parallel. The transmission axis 43 a of the third polarizing plate 43 provided on the liquid crystal display element 20 is substantially perpendicular to the transmission axis 41 a of the first polarizing plate 41 and the transmission axis 42 a of the second polarizing plate 42 .

The viewing angle switching layer 11 includes a liquid crystal composition (liquid crystal composition for viewing angle adjustment element of the present invention) containing liquid crystal molecules 11m and having positive dielectric anisotropy. On the transparent electrodes 12a and 12b, there are rubbing-treated alignment films (not shown) for aligning the liquid crystal molecules 11m. In this embodiment, as shown in FIG. 2 , the rubbing direction Ra of the alignment film for the transparent electrode 12a is substantially parallel to and opposite to the rubbing direction Rb of the alignment film for the transparent electrode 12b. That is, the viewing angle switching layer 11 is a parallel (homogeneous) alignment (horizontally aligned) liquid crystal layer, and the liquid crystal molecules 11m contained in the viewing angle switching layer 11 are arranged in a manner such that the molecular long axis 11a is roughly parallel to the transparent substrate 13a, the transparent substrate 13b and the transparent electrode 12a, the transparent electrode 12b when no voltage is applied.

In addition, the molecular long axis 11a of the liquid crystal molecule 11m included in the viewing angle switching layer 11 is substantially perpendicular to the transmission axis 41a of the first polarizing plate 41 disposed between the backlight 30 and the viewing angle adjustment element 10, and the transmission axis 42a of the second polarizing plate 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20. When no voltage is applied to the viewing angle switching layer 11, incident light perpendicularly incident on the viewing angle switching layer 11 in the front direction (viewing angle 0°) 50a of the liquid crystal display device 1, and incident light incident on the viewing angle switching layer 11 from directions 50b and 50c having a predetermined angle all pass through the second polarizing plate 42, and are incident on the liquid crystal display element 20, and then pass through the third polarizing plate 43.

If a voltage is applied to the viewing angle switching layer 11 using a pair of transparent electrodes 12a and transparent electrodes 12b, the liquid crystal molecules 11m contained in the viewing angle switching layer 11 are arranged in the following state according to the magnitude of the applied voltage: along the direction of the dotted arrows in Figures 1 and 2, the molecular long axis 11a is maintained approximately perpendicular to the transmission axis 41a of the first polarizing plate 41 and the transmission axis 42a of the second polarizing plate 42, while being tilted at an acute angle (for example, 20°, 45°, 70°, etc.) from being approximately parallel to the transparent substrates 13a and 13b and the transparent electrodes 12a and 12b. Therefore, after passing through the first polarizer 41 disposed between the backlight 30 and the viewing angle adjustment element 10, the incident light that is incident on the viewing angle switching layer 11 from directions 50b and 50c that are not perpendicular but have a specified angle is phase delayed, and is thus unable to pass through the second polarizer 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20. Only the incident light that is incident on the viewing angle switching layer 11 perpendicularly from the front direction 50a of the liquid crystal display device 1 passes through the second polarizer 42, is incident on the liquid crystal display element 20, and then passes through the third polarizer 43.

In this way, by applying a voltage to the viewing angle switching layer 11 of the viewing angle adjustment element 10, the viewing angle characteristic of the liquid crystal display device 1 can be switched from a wide viewing angle to a narrow viewing angle.

Fig. 3 is a schematic cross-sectional view showing the structure of an example of a liquid crystal display device according to another embodiment of the present invention. Fig. 4 is an exploded perspective view of the liquid crystal display device shown in Fig. 3. The liquid crystal display device shown in Figs. 3 and 4 is an example of a liquid crystal display device using a liquid crystal composition having negative dielectric anisotropy in a viewing angle switching layer.

The liquid crystal display device 1 shown in FIG. 3 and FIG. 4 includes: a viewing angle adjustment element 10 for switching the viewing angle characteristics of the liquid crystal display device 1; a liquid crystal display element 20; a backlight 30; a first polarizer 41 disposed between the backlight 30 and the viewing angle adjustment element 10; a second polarizer 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20; and a third polarizer 43 disposed on the liquid crystal display element 20. In the description of FIG. 3 and FIG. 4 , light incident on the liquid crystal display element 20 passes through the polarizer 43.

The viewing angle adjustment element 10 includes: a first light-transmitting substrate 13a having a first transparent electrode 12a on the surface; and a second light-transmitting substrate 13b having a second transparent electrode 12b on the surface; and a viewing angle switching layer 11, which is sandwiched by a pair of transparent electrodes 12a and a transparent electrode 12b, and the pair of transparent electrodes 12a and a transparent electrode 12b can apply a voltage to the viewing angle switching layer 11. In the liquid crystal display device 1, an alignment film (not shown) is also provided on the transparent electrodes 12a and the transparent electrodes 12b. The transmission axis 41a of the first polarizing plate 41 disposed between the backlight 30 and the viewing angle adjustment element 10 and the transmission axis 42a of the second polarizing plate 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20 are substantially parallel. The transmission axis 43 a of the third polarizing plate 43 provided on the liquid crystal display element 20 is substantially perpendicular to the transmission axis 41 a of the first polarizing plate 41 and the transmission axis 42 a of the second polarizing plate 42 .

The viewing angle switching layer 11 includes a liquid crystal composition (liquid crystal composition for viewing angle adjustment element of the present invention) containing liquid crystal molecules 11m' and having negative dielectric anisotropy. In the present embodiment, the viewing angle switching layer 11 is a vertically aligned liquid crystal layer, and the liquid crystal molecules 11m' contained in the viewing angle switching layer 11 are arranged in a manner that the molecular long axis 11a' is substantially perpendicular to the light-transmitting substrate 13a, the light-transmitting substrate 13b and the transparent electrodes 12a, the transparent electrodes 12b when no voltage is applied.

When no voltage is applied to the viewing angle switching layer 11, incident light vertically incident on the viewing angle switching layer 11 in the front direction (viewing angle 0°) 50a of the liquid crystal display device 1, and incident light incident on the viewing angle switching layer 11 from directions 50b and 50c with specified angles all pass through the second polarizer 42, and are incident on the liquid crystal display element 20, and then pass through the third polarizer 43.

If a voltage is applied to the viewing angle switching layer 11 using a pair of transparent electrodes 12a and 12b, the liquid crystal molecules 11m' contained in the viewing angle switching layer 11 are arranged in the following state according to the magnitude of the applied voltage: along the direction of the dotted arrows in Figures 3 and 4, the molecular long axis 11a' is maintained approximately perpendicular to the transmission axis 41a of the first polarizing plate 41 and the transmission axis 42a of the second polarizing plate 42, while being tilted at an acute angle from being approximately perpendicular to the transparent substrates 13a and 13b and the transparent electrodes 12a and 12b. Therefore, after passing through the first polarizer 41 disposed between the backlight 30 and the viewing angle adjustment element 10, the incident light that is incident on the viewing angle switching layer 11 from directions 50b and 50c that are not perpendicular but have a specified angle is phase delayed, and is thus unable to pass through the second polarizer 42 disposed between the viewing angle adjustment element 10 and the liquid crystal display element 20. Only the incident light that is incident on the viewing angle switching layer 11 perpendicularly from the front direction 50a of the liquid crystal display device 1 passes through the second polarizer 42, is incident on the liquid crystal display element 20, and then passes through the third polarizer 43.

In this way, by applying a voltage to the viewing angle switching layer 11 of the viewing angle adjustment element 10, the viewing angle characteristic of the liquid crystal display device 1 can be switched from a wide viewing angle to a narrow viewing angle.

Furthermore, a liquid crystal display element needs to drive the liquid crystal with display units such as pixel units or segment units, and has an electrode structure corresponding to the display unit, but the electrode structure of the viewing angle adjustment element is not particularly limited. For example, in order to perform the same switching on the entire display surface, the same transparent electrodes 12a and transparent electrodes 12b can be formed on the entire surface of the transparent substrate 13a and the transparent substrate 13b, or they can be formed into any other shape, such as a desired patterned shape.

In FIG. 1 and FIG. 2, FIG. 3 and FIG. 4, the following liquid crystal display device 1 is illustrated, that is, when no voltage is applied, the incident light entering the viewing angle switching layer 11 from any direction of the front direction 50a of the liquid crystal display device 1, the direction 50b with a specified angle, and the direction 50c all passes through the second polarizer 42, and is incident on the liquid crystal display element 20, and then also passes through the third polarizer 43, thereby becoming a wide viewing angle display, and when voltage is applied, only the incident light entering the viewing angle switching layer 11 from the front direction 50a of the liquid crystal display device 1 passes through the second polarizer 42, and is incident on the liquid crystal display element 20, and then also passes through the third polarizer 43, thereby becoming a narrow viewing angle display, but the liquid crystal display device of the present invention and the viewing angle adjustment element of the present invention are not limited to this. For example, the liquid crystal display device 1 may be configured as follows: when no voltage is applied, only the incident light entering the viewing angle switching layer 11 from the front direction 50a of the liquid crystal display device 1 passes through the second polarizer 42, enters the liquid crystal display element 20, and further passes through the third polarizer 43, thereby achieving a narrow viewing angle display; and when voltage is applied, the incident light entering the viewing angle switching layer 11 from any of the front direction 50a of the liquid crystal display device 1, the direction 50b with a specified angle, and the direction 50c all passes through the second polarizer 42, enters the liquid crystal display element 20, and further passes through the third polarizer 43, thereby achieving a wide viewing angle display.

In Figures 1 and 2, 3 and 4, the following liquid crystal display device 1 is illustrated, that is, the transmission axis 41a of the first polarizer 41 arranged between the backlight 30 and the viewing angle adjustment element 10, and the transmission axis 42a of the second polarizer 42 arranged between the viewing angle adjustment element 10 and the liquid crystal display element 20 are approximately parallel, but the transmission axis 41a of the first polarizer 41 arranged between the backlight 30 and the viewing angle adjustment element 10, and the transmission axis 42a of the second polarizer 42 arranged between the viewing angle adjustment element 10 and the liquid crystal display element 20 may also be arranged in a manner that is approximately orthogonal to each other.

In addition, in Figures 1 and 2, Figures 3 and 4, a liquid crystal display device 1 is illustrated which sequentially includes a backlight 30, a first polarizing plate 41, a viewing angle adjustment element 10, a second polarizing plate 42, a liquid crystal display element 20, and a third polarizing plate 43. However, a liquid crystal display device may also sequentially include a backlight, a first polarizing plate, a liquid crystal display element, a second polarizing plate, a viewing angle adjustment element, and a third polarizing plate. That is, a liquid crystal display element may be provided between the backlight and the viewing angle adjustment element instead of a viewing angle adjustment element provided between the backlight and the liquid crystal display element.

Furthermore, the liquid crystal display device 1 shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4 includes a viewing angle adjustment element 10 for switching the viewing angle characteristics of the liquid crystal display device 1, but the liquid crystal display device may also include more than two viewing angle adjustment elements. The more than two viewing angle adjustment elements may be the same or different.

The liquid crystal display device may further include a phase difference plate for setting the viewing restriction direction between the liquid crystal display element and the viewing angle adjustment element. By providing an appropriate phase difference plate between the liquid crystal display element and the viewing angle adjustment element, the polarization direction (the direction of the polarization axis) of the linear polarization passing through the viewing angle adjustment element or the liquid crystal display element can be changed, thereby using the viewing angle adjustment element to change the viewing restriction direction. That is, by using an appropriate phase difference plate and appropriately setting its axis, the viewing restriction direction at a narrow viewing angle can be arbitrarily set.

When a phase difference plate is provided, the phase difference plate may be provided between polarizing plates. That is, the liquid crystal display device may include, for example, a backlight, a first polarizing plate, a liquid crystal display element, a second polarizing plate, a phase difference plate, a third polarizing plate, a viewing angle adjustment element, and a fourth polarizing plate in sequence.

The phase difference plate is not particularly limited, and may be, for example, a 1/2 wavelength plate (1/2λ plate). In the case of a liquid crystal display device that includes a backlight, a first polarizing plate, a liquid crystal display element, a second polarizing plate, a phase difference plate, a third polarizing plate, a viewing angle adjustment element, and a fourth polarizing plate in sequence, the second polarizing plate and the third polarizing plate are arranged in such a way that the angle formed by the transmission axis of the second polarizing plate and the axis of the 1/2 wavelength plate and the angle formed by the axis of the 1/2 wavelength plate and the transmission axis of the third polarizing plate are equal, thereby maintaining the intensity of the linear polarization passing through the liquid crystal display element while changing its polarization direction (direction of the polarization axis). The phase difference plate may also be composed of two 1/4 wavelength plates arranged in parallel, that is, with their respective axes parallel.

Furthermore, a phase difference plate may be provided between the first polarizing plate and the liquid crystal display element and/or between the second polarizing plate and the liquid crystal display element. A phase difference plate may be provided between the third polarizing plate and the viewing angle adjustment element and/or between the fourth polarizing plate and the viewing angle adjustment element. By providing a phase difference plate between the polarizing plate and the viewing angle adjustment element, elliptical polarization generated by double refraction of the viewing angle switching layer (liquid crystal layer) of the viewing angle adjustment element can be optically compensated, light leakage can be suppressed, and viewing angle characteristics in narrow viewing angle display can be improved.

In addition, the liquid crystal display device may further include a compensation film containing liquid crystal molecules between the liquid crystal display element and the viewing angle adjustment element. When such a compensation film containing liquid crystal molecules is provided, the compensation film may be provided between polarizing plates. That is, the liquid crystal display device may include, for example, a backlight, a first polarizing plate, a viewing angle adjustment element, a second polarizing plate, a compensation film containing liquid crystal molecules, a third polarizing plate, a liquid crystal display element, and a fourth polarizing plate in sequence. The liquid crystal display device may also include, in sequence, a backlight, a first polarizing plate, a liquid crystal display element, a second polarizing plate, a viewing angle adjustment element, a third polarizing plate, a compensation film containing liquid crystal molecules, and a fourth polarizing plate. The liquid crystal display device may also be configured to include a backlight, a first polarizing plate, a compensation film containing liquid crystal molecules, a second polarizing plate, a viewing angle adjustment element, a third polarizing plate, a liquid crystal display element, and a fourth polarizing plate in sequence. By providing a compensation film containing liquid crystal molecules, light leakage in a wide angle range can be suppressed, and a better viewing angle adjustment function can be achieved.

The liquid crystal molecules contained in the compensation film containing liquid crystal molecules may have their long axes substantially perpendicular to the substrate, substantially parallel to the substrate, or inclined at an acute angle to the substrate. The liquid crystal molecules contained in the compensation film containing liquid crystal molecules are not particularly limited, and known liquid crystal compounds may be used.

The liquid crystal display device may also include two or more compensation films containing liquid crystal molecules. The two or more compensation films containing liquid crystal molecules may be the same or different. When two or more compensation films containing liquid crystal molecules are provided, their positions may be selected without particular limitation.

Furthermore, the liquid crystal display device may also include both the above-mentioned phase difference plate and the compensation film containing liquid crystal molecules.

The viewing angle adjustment element of the present invention and the display device such as the liquid crystal display device of the present invention can be manufactured according to a known method by using the liquid crystal composition for the viewing angle adjustment element of the present invention in the viewing angle switching layer. [Example]

The present invention is described in more detail by way of examples. The present invention is not limited to these examples. The present invention also includes, for example, a mixture of at least two of the compositions of Examples 1 to 3 (Compositions 1 to 3) and the compositions of Compositions 1 to 23. The synthesized compound is identified by methods such as nuclear magnetic resonance (NMR) analysis. The properties of the compounds, compositions, and components are measured by the methods described below.

NMR analysis: DRX-500 manufactured by Bruker BioSpin was used for the measurement. In the ¹ H-NMR measurement, the sample was dissolved in a deuterated solvent such as CDCl ₃ , and the measurement was performed at room temperature at 500 MHz and 16 cumulative times. Tetramethylsilane was used as an internal standard. In the ¹⁹ F-NMR measurement, CFCl ₃ was used as an internal standard and the measurement was performed at 24 cumulative times.

Gas chromatography analysis: A GC-14B gas chromatograph manufactured by Shimadzu Corporation was used for the measurement. The carrier gas was helium (2 mL/min). The sample vaporization chamber was set to 280°C, and the detector (flame ionization detector (FID)) was set to 300°C. A capillary column DB-1 (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm; stationary liquid phase was dimethyl polysiloxane; non-polar) manufactured by Agilent Technologies Inc. was used for the separation of the component compounds. The column was kept at 200°C for 2 minutes and then heated to 280°C at a rate of 5°C/min. After the sample was prepared as an acetone solution (0.1 mass %), 1 μL of it was injected into the sample vaporization chamber. The recording instrument is a C-R5A chromatograph unit (Chromatopac) manufactured by Shimadzu Corporation or its equivalent. The obtained gas chromatogram shows the retention time and peak area of the peak corresponding to the component compound.

The solvent used to dilute the sample can be chloroform, hexane, etc. To separate the component compounds, the following capillary columns can be used: HP-1 manufactured by Agilent Technologies Inc. (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm), Rtx-1 manufactured by Restek Corporation (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm), BP-1 manufactured by SGE International Pty. Ltd of Australia (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm). In order to prevent the overlap of compound peaks, a capillary column CBP1-M50-025 (length 50 m, inner diameter 0.25 mm, film thickness 0.25 μm) manufactured by Shimadzu Corporation was used.

The ratio of the liquid crystal compound contained in the composition can be calculated by the following method. The mixture of liquid crystal compounds is analyzed by gas chromatograph (FID). The area ratio of the peaks in the gas chromatogram is equivalent to the ratio of the liquid crystal compound. When using the capillary column described above, the correction factor of each liquid crystal compound can be regarded as 1. Therefore, the ratio (mass %) of the liquid crystal compound can be calculated based on the area ratio of the peaks.

Test sample: When measuring the properties of a component or element, the component is directly used as a sample.

Measurement method: The characteristics were measured using the following methods. Most of these methods are methods described in the JEITA standard (JEITA ED-2521B) reviewed and established by the Japan Electronics and Information Technology Industries Association (JEITA), or modified methods. The TN element used in the measurement does not have a thin film transistor (TFT) mounted on it.

The measurement method may differ depending on whether the dielectric anisotropy of the sample is positive or negative. Measurements (18) to (21a), (21b), and (21c) are measurement methods for samples with negative dielectric anisotropy.

(1) Upper limit temperature of the nematic phase (NI; °C): Place a sample on a heating plate of a melting point measuring device equipped with a polarizing microscope and heat it at a rate of 1 °C/min. Measure the temperature at which a portion of the sample changes from the nematic phase to an isotropic liquid. The upper limit temperature of the nematic phase is sometimes referred to as the "upper limit temperature".

(2) Lower limit temperature of nematic phase (T _C ; ℃): A sample having a nematic phase is placed in a glass bottle and stored in a freezer at 0℃, -10℃, -20℃, -30℃ and -40℃ for 10 days, and the liquid crystal phase is observed. For example, when the sample maintains a nematic phase at -20℃ and changes to a crystalline or lamellar phase at -30℃, it is recorded as T _C <-20℃. The lower limit temperature of the nematic phase is sometimes referred to as the "lower limit temperature".

(3) Viscosity (volume viscosity; η; measured at 20°C; mPa·s): The measurement was performed using an E-type rotational viscometer manufactured by Tokyo Keiki Co., Ltd.

(4) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s): The measurement was carried out according to the method described in M. Imai et al., "Molecular Crystals and Liquid Crystals" (Vol. 259, 37 (1995)). The sample was placed in a TN device with a twist angle of 0° and a distance (cell gap) between two glass substrates of 5 μm. A voltage was applied to the device in steps of 0.5 V in the range of 16 V to 19.5 V. After no voltage was applied for 0.2 seconds, the voltage was repeatedly applied with only one rectangular wave (rectangular pulse; 0.2 seconds) and no application (2 seconds). The peak current and peak time of the transient current generated by the application are measured. The rotational viscosity value is obtained from these measured values and the calculation formula (10) described on page 40 of the paper by M. Imai et al. The value of the dielectric anisotropy required for the calculation is obtained by using the element for measuring the rotational viscosity and the method described below.

(5) Optical anisotropy (refractive index anisotropy; Δn; measured at 25°C): Measured using an Abbe refractometer with a polarizing plate mounted on the eyepiece, using light of a wavelength of 589 nm. After rubbing the surface of the main prism in one direction, drop the sample onto the main prism. When the direction of polarization is parallel to the direction of rubbing, the refractive index n∥ is measured. When the direction of polarization is perpendicular to the direction of rubbing, the refractive index n⊥ is measured. The value of optical anisotropy is calculated using the formula Δn = n∥ - n⊥.

(6) Dielectric anisotropy (Δε; measured at 25°C): A sample was placed in a TN device with a distance between two glass substrates (cell gap) of 9 μm and a twist angle of 80 degrees. A sine wave (10 V, 1 kHz) was applied to the device, and after 2 seconds, the dielectric constant (ε∥) of the liquid crystal molecules in the long axis direction was measured. A sine wave (0.5 V, 1 kHz) was applied to the device, and after 2 seconds, the dielectric constant (ε⊥) of the liquid crystal molecules in the short axis direction was measured. The value of dielectric anisotropy is calculated according to the formula Δε = ε∥ - ε⊥.

(7) Threshold voltage (Vth; measured at 25°C; V): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The sample was placed in a normally white mode TN element in which the distance between the two glass substrates (cell gap) was 0.45/Δn (μm) and the twist angle was 80 degrees. The voltage applied to the element (32 Hz, rectangular wave) was increased stepwise from 0 V to 10 V in steps of 0.02 V. At this time, light was irradiated to the element from a vertical direction, and the amount of light passing through the element was measured. A voltage-transmittance curve was prepared in which the transmittance was 100% when the light amount reached a maximum, and the transmittance was 0% when the light amount was a minimum. The threshold voltage is expressed by the voltage at which the transmittance reaches 90%.

(8) Voltage retention ratio (VHR-9; measured at 25°C; %): The TN element used in the measurement has a polyimide alignment film and the distance between the two glass substrates (cell gap) is 5 μm. After the sample is placed, the element is sealed using an adhesive that cures by ultraviolet light. A pulse voltage (1 V, 60 microseconds) is applied to the TN element for charging. The attenuated voltage is measured over a period of 166.7 milliseconds using a high-speed voltmeter, and the area A between the voltage curve and the horizontal axis per unit cycle is calculated. Area B is the area when the voltage is not attenuated. The voltage retention ratio is expressed as a percentage of area A relative to area B.

(9) Voltage holding ratio (VHR-10; measured at 60°C; %): The voltage holding ratio was measured in the same manner as described above, except that the measurement was performed at 60°C instead of 25°C. The obtained value is expressed as VHR-10.

(10) Voltage holding ratio (VHR-11; measured at 60°C; %): After irradiation with ultraviolet rays, the voltage holding ratio was measured to evaluate the stability to ultraviolet rays. The TN element used in the measurement had a polyimide alignment film and a cell gap of 5 μm. The sample was injected into the element and irradiated with ultraviolet rays of 5 mW/ ^cm2 for 167 minutes. The light source was a black light, F40T10/BL (peak wavelength 369 nm) manufactured by Eyegraphis Co., Ltd., and the distance between the element and the light source was 5 mm. In the measurement of VHR-11, the attenuated voltage was measured within a period of 166.7 milliseconds. A composition with a large VHR-11 has a large stability to ultraviolet rays.

(11) Voltage holding ratio (VHR-12; measured at 60°C; %): After heating the TN device injected with the sample in a constant temperature bath at 120°C for 20 hours, the voltage holding ratio was measured to evaluate the thermal stability. In the VHR-12 measurement, the voltage attenuation was measured over a period of 166.7 milliseconds. A composition with a large VHR-12 has a high thermal stability.

(12) Voltage holding ratio (VHR-13; measured at 60°C; %): After heating the TN device injected with the sample in a constant temperature bath at 100°C for 3 weeks, the voltage holding ratio was measured to evaluate the thermal stability. In the VHR-13 measurement, the voltage attenuation was measured over a period of 166.7 milliseconds. A composition with a large VHR-13 has a high thermal stability.

(13a) Response time (τa; measured at 25°C; ms): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The low-pass filter was set to 5 kHz. The sample was placed in a normally white mode TN element in which the distance between two glass substrates (cell gap) was 3.4 μm and the twist angle was 80 degrees. A rectangular wave (60 Hz, 5 V, 0.5 seconds) was applied to the element. At this time, light was irradiated to the element from a vertical direction, and the amount of light passing through the element was measured. When the light amount reached a maximum, the transmittance was considered to be 100%, and when the light amount was a minimum, the transmittance was considered to be 0%. The rise time (τr: rise time; milliseconds) is the time required for the transmittance to change from 90% to 10%. The fall time (τf: fall time; milliseconds) is the time required for the transmittance to change from 10% to 90%. The response time is expressed by the sum of the rise time and the fall time obtained in the above manner.

(13b) Response time (τb; measured at -20°C; ms): The response time (τb) was obtained by the same procedure as described above, except that the measurement was performed at -20°C instead of 25°C.

(13c) Response time (τc; measured at -30°C; ms): The response time (τc) was obtained in the same manner as described above, except that the measurement was performed at -30°C instead of 25°C.

(14) Elastic constant (K; measured at 25°C; pN): The measurement was performed using an HP4284A LCR meter manufactured by Yokogawa Hewlett-Packard Co., Ltd. A sample was placed in a horizontally aligned element in which the distance between two glass substrates (cell gap) was 20 μm. A charge of 0 volts to 20 volts was applied to the element, and the electrostatic capacitance and applied voltage were measured. The values of the measured electrostatic capacitance (C) and applied voltage (V) were fitted using equations (2.98) and (2.101) on page 75 of the Liquid Crystal Device Handbook (Nikkan Kogyo Shimbun), and the values of K11 and K33 were obtained from equation (2.99). Next, the values of K11 and K33 obtained previously are used in formula (3.18) on page 171 of the Liquid Crystal Device Handbook to calculate K22. The elastic constant is represented by the average value of K11, K22, and K33 obtained in the above manner.

(15) Specific resistance (ρ; measured at 25°C; Ωcm): 1.0 mL of a sample is injected into a container including electrodes. A DC voltage (10 V) is applied to the container, and the DC current is measured after 10 seconds. The specific resistance is calculated by the following formula. (Specific resistance) = {(voltage) × (capacitance of container)} / {(DC current) × (dielectric constant of vacuum)}.

(16) Helical pitch (P; measured at room temperature; μm): The helical pitch is measured using the wedge method. See Liquid Crystal Handbook, page 196 (published in 2000, Maruzen). The sample is injected into the wedge cell and left to stand at room temperature for 2 hours. The interval (d2-d1) of the disclination lines is then observed using a polarizing microscope (Nikon Co., Ltd., trade name MM40/60 series). The helical pitch (P) is calculated using the following formula, where the angle of the wedge cell is represented by θ. P = 2×(d2-d1)×tanθ.

(17) Transmittance (T; measured at 25°C; %): The measurement was performed using an LCD-5200 luminance meter manufactured by OTSUKA Co., Ltd. Before measuring the brightness, first turn on the light source and preheat for 30 minutes. Install the element injected with the composition between the polarizer and the analyzer of the optical measurement module. While applying voltage, adjust the element orientation direction and the appropriate angles of the polarizer and the analyzer in a manner to minimize the amount of light, so that the element orientation direction and the angles of the polarizer and the analyzer are fixed. Using the built-in waveform generator, increase the voltage to the element from 0 V to 12 V (peak to peak) in steps of 0.2 V (peak to peak), and repeat. Using the LCD-5200 luminance meter, measure the amount of light passing through the element at each voltage. Using the brightness values obtained above, the transmittance at each applied voltage is calculated by the following formula, and the transmittance at an applied voltage of 0 V is set to 100% and normalized. (Relative transmittance at a viewing angle of X°) = {(amount of light at a viewing angle of X°) / (amount of light at the front (viewing angle of 0°))} × 100.

The following is a method for measuring negative dielectric anisotropy.

(18) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s): The measurement was performed using a rotational viscosity measurement system LCM-2 manufactured by Toyo Technica Co., Ltd. The sample was injected into a VA element having a distance (cell gap) of 10 μm between two glass substrates. A rectangular wave (55 V, 1 ms) was applied to the element. The peak current and peak time of the transient current generated by the application were measured. The rotational viscosity value was obtained using these measured values and the dielectric anisotropy. The dielectric anisotropy was measured using the method described in measurement (6).

(19) Dielectric anisotropy (Δε; measured at 25°C): The value of dielectric anisotropy is calculated by the formula Δε=ε∥-ε⊥. The dielectric constants (ε∥ and ε⊥) are measured as follows. 1) Measurement of dielectric constant (ε∥): A solution of octadecyltriethoxysilane (0.16 mL) in ethanol (20 mL) is applied to a thoroughly cleaned glass substrate. The glass substrate is rotated using a rotator and then heated at 150°C for 1 hour. A sample is placed in a VA element with a distance (cell gap) of 4 μm between the two glass substrates, and the element is sealed using an adhesive cured by ultraviolet light. A sine wave (0.5 V, 1 kHz) is applied to the element, and the dielectric constant (ε∥) of the liquid crystal molecules in the long axis direction is measured after 2 seconds. 2) Measurement of dielectric constant (ε⊥): A polyimide solution is applied to a thoroughly cleaned glass substrate. After the glass substrate is calcined, the obtained alignment film is subjected to a friction treatment. A sample is placed in a TN element in which the distance (unit gap) between the two glass substrates is 9 μm and the twist angle is 80 degrees. A sine wave (0.5 V, 1 kHz) is applied to the element, and the dielectric constant (ε⊥) of the liquid crystal molecules in the short axis direction is measured after 2 seconds.

(20) Threshold voltage (Vth; measured at 25°C; V): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing direction was antiparallel, and the element was sealed using an adhesive that was cured by ultraviolet light. The voltage applied to the element (60 Hz, rectangular wave) was increased stepwise from 0 V to 20 V in steps of 0.02 V. At this time, light was irradiated to the element from a vertical direction, and the amount of light passing through the element was measured. A voltage-transmittance curve was prepared in which the transmittance was 100% when the light amount reached a maximum, and the transmittance was 0% when the light amount was a minimum. The threshold voltage is expressed by the voltage at which the transmittance reaches 10%.

(21a) Response time (τ; measured at 25°C; ms): The measurement was performed using an LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. The light source was a halogen lamp. The low-pass filter was set to 5 kHz. 1) Composition not containing a polymerizable compound: A sample was placed in a normally black mode VA element in which the distance between two glass substrates (cell gap) was 4 μm and the rubbing direction was antiparallel. The element was sealed using an adhesive cured by ultraviolet light. A rectangular wave (60 Hz, 10 V, 0.5 seconds) was applied to the element. At this time, light was irradiated from the vertical direction to measure the amount of light passing through the element. When the light amount reached the maximum, the transmittance was considered to be 100%, and when the light amount was the minimum, the transmittance was considered to be 0%. The response time is expressed as the time required for the transmittance to change from 90% to 10% (fall time; milliseconds).

(21b) Response time (τb; measured at -20°C; ms): The response time (τb) was obtained by the same procedure as described above, except that the measurement was performed at -20°C instead of 25°C.

(21c) Response time (τc; measured at -30°C; ms): The response time (τc) was obtained by the same procedure as described above, except that the measurement was performed at -30°C instead of 25°C.

The following are examples of compositions. The component compounds are represented by symbols based on the definitions in Table 3 below. In Table 3, the stereo configuration associated with 1,4-cyclohexyl is the trans configuration. The numbers in parentheses after the labeled compounds indicate the chemical formula to which the compounds belong. The symbol (-) refers to other liquid crystal compounds. The ratios (percentages) of the component compounds recorded below are mass percentages (mass %) based on the mass of the liquid crystal composition. Finally, the characteristic values of the composition are summarized.

[Composition 1] 3-HH-V （1-1） 28% 1-BB-3 （1-3）                                                                                                                                                                                                                     not not not not not not have been                       5% 3-BB(F more not more more likely? )B-5                                                     5-HBB(F)                                        -HBB(F)B-3 (1-13) 8% 3-BB(F)B (F,F)-F (2-15) 13% 3-BB (F,F) 4% 3-HBB(F)-F 5 % 5-HBB(F)-F                           （2）                       8% NI=89.9℃；Tc＜-30℃；Δn=0.151；Δε=4.8；Vth=2.17 V；γ1=83.0 mPa·s。

[Composition 2] 7-HB-1                                                                                                                            1-BB-3 10% 2-BB(F)B-3 (1-3) 1-BB-3 (1-8) 5% 2-BB(F)B-5 （1-8） 7% 3-BB(F)B-5 (1-8) 7% 5-HBB(F)B-2 (1 -13) 12% 5-HBB(F)B-3                                                                                        8% 3-BB(F,F)XB(F,F)-F (2-18) 13% 3-BB(F,F)XB(F)B(F,F)-F （2-30） 13% NI=103.4℃; Tc＜-40℃; eta=42.4 mPa· s; Δn=0.201; Δε=6.1; Vth=2.46 V; γ1=234.0 mPa·s.

[Composition 3] 3-HH-V （1-1） 27% 2-BB(F)B-3 （1-8）            9% 2-BB(F)B-5                                                                        8% 3 -BB(F)B-5                            （1-8）                    10% 1-BB(F)B-2V                         （1-8）                    5% 2-BB(F)B-2V                         （1-8）                    7% 3-BB (F)B-2V                                                                              6% 5-HBB(F)B-2 (1-13) 5% 5-HBB(F)B-3 (1-13) 5% 3-BB(F,F)XB(F,F)-F (2-18) 15% 3-BB(F,F)XB(F)B(F,F)-F （2-30） 3% NI=101.8℃; Tc＜-30℃; η=20.4 mPa· s; Δn=0.181; Δε=3.7.

[Example 1 to Example 3] A polyimide alignment film was formed on a glass substrate formed with an ITO (Indium Tin Oxide) electrode (thickness: about 60 nm), and the composition 1 to the composition 3 were injected between the substrates to form a viewing angle switching layer, thereby manufacturing a viewing angle adjustment element. The transmittance at a viewing angle of 0° (front) and a viewing angle of 45° when a voltage was applied to the viewing angle switching layer was measured. The results are summarized in Table 4. In the table, d is the thickness of the viewing angle switching layer, and Δn is the optical anisotropy of the composition. Table 4. Transmittance Embodiment Liquid crystal composition d (μm) Δn×d (nm) Applied voltage (Vpp) Transmittance Viewing angle 0° Viewing angle 45° 1 Composition 1 4.85 732 0 100.0% 100.0% 6.6 100.0% 7.0% 5 755 0 100.0% 100.0% 6.6 100.0% 6.4% 2 Composition 2 3.7 745 0 100.0% 100.0% 7.0 100.0% 7.8% 3.8 764 0 100.0% 100.0% 7.0 100.0% 7.0% 3.9 784 0 100.0% 100.0% 7.2 100.0% 6.5% 3 Composition 3 3.8 688 0 100.0% 100.0% 7.8 100.0% 11.5% 4.2 760 0 100.0% 100.0% 8.0 100.0% 7.1% 4.35 787 0 100.0% 100.0% 8.2 100.0% 5.6%

As shown in the results of Table 4, in the front view (viewing angle 0°), the transmittance does not change when no voltage is applied and when voltage is applied. On the other hand, in the viewing angle direction of 45°, the transmittance decreases significantly when voltage is applied. It is known that by using the liquid crystal composition of the present invention in the viewing angle switching layer of the viewing angle adjustment element, a display device with a wide viewing field when no voltage is applied to the viewing angle switching layer and a narrow viewing field when voltage is applied can be realized.

The following are examples of the compositions of the present invention. The liquid crystal compositions of Composition Examples 1 to 24 can all be used in the viewing angle switching layer of the viewing angle adjustment element. [Composition example 1] 3-HH-V                                                                                                              5.5% 2-BB(F)B-3 （1-8） 9% 2-BB(F)B-5 (1-8) 8% 3-BB(F)B-5 1-8 1-BB(F)B-2V (1-8) 5% 2-BB(F)B-2V (1-8) 7% 3-BB(F)B-2V (1-8) 6% 5-HBB(F)B-2 （1-13） 5% 5-HBB(F)B-3 （1-13） 5% 3-BB(F,F)XB(F,F)-F （2-18） 15% 3-BB(F,F)XB(F)B(F,F)-F （2-30） 3% NI=98.3℃; Tc＜-40℃; eta=19.6 mPa·s; Δn=0.190 ;Δε=3.8.

[Composition example 2] 3-HB-O2                                                                                                                                  )               13% 1-BB(F)            (1-8)         5% 2-BB( F)B-2V (1-8) 5% 3-BB(F)B-2V (1-8) 5% -HBB(F)B-2 (1-13) 6% 5-HBB(F) B-3 (1-13) 6% 3-BB(2F,5F)B-3 (1) 10% 3-BB(F)B(F,F)-F (2-15) 12% 3-BB(F,F)XB(F ,F)-F (2-18) 4% 4-BB(F)B(F,F)XB(F,F)-F (2-29) 6% 3-BB(F,F)XB(F )B(F,F)-F (2-30) 13% NI=88.1℃; Tc＜-20℃; Δn=0.203; Δε=8.7.

[組成物例3] 3-HB-O2                                     （1-2）                    17% 1-BB-2                                   （1-3）                    11% 3-BB(F)B-5                            （1-8）                    4% 1-BB( F)B-2V                         （1-8）                    5% 2-BB(F)B-2V                         （1-8）                    5% 3-BB(F)B-2V                         （1-8）                    6% 5-HBB(F) B-2                                                                          7% 5-HBB(F)B-3                                                                                      12% 3-BB(F,F)XB(F ,F)-F (2-18) 4% 4-BB(F)B(F,F)XB(F,F)-F (2-29) 6% 3-BB(F,F)XB(F )B(F,F)-F (2-30) 13% 3-HBB(F)-F (2) 3% NI=95.0℃; Tc＜-30℃; Δn=0.199; Δε=9.0.

[Composition example 4] 3-HH-V                                                                                                                      8% 1-BB-3 5% 2-BB(F)B- 3                                                                 5% 3-BB(F)B-5                                                                                                                1-8)                    4% 2-BB(F)B-2V                                                                            5% 5-HBB(F)B-2 （1-13） 6% 5-HBB(F)B-3 (1-13) 6% 3-BB(2F,5F)B-3 (1) 8% 3-BB(F,F)XB(F,F)-F (2 -18）           18% 4-BB(F)B(F,F)XB(F,F)-F      (2-29) 4% 3-BB(F,F)XB(F)B(F,F)-F （2-30） 13% NI=93.8℃; Tc＜-30℃; Δn=0.199; Δε =9.3; Vth=1.92 V; γ1=179.0 mPa·s.

[Composition Example 5] 3-HB-O2                                     （1-2）                      12% 5-HB-O2                                     （1-2）                    12% 2-HHB-1                                      （1-5）                      3% 3-HHB-1                                       （1-5）                      6% 3-HHB-O1                                  （1-5） 8% 3-BB(F)B-5                                                                                      5% 3-HBB(F,F)XB(F,F)-F （2-24） 7% 3-BB(F)B(F,F)XB(F,F)-F （2-29） 3% 4-BB(F)B(F,F)XB(F,F)-F （2-29） 4% 3-BB(F,F)XB(F)B(F,F)-F （2-30） 12% 3-HHB-F                                 (2) 5% 3-HBB-F (2) 5% NI=104.5℃; T c＜-30℃; η=39.7 mPa·s; Δn=0.167; Δε=6.4; Vth=2.27 V.

[Composition Example 6] 2-HH-3                                     （1-1）                      12% 3-HB-O2                                     （1-2）                    7% 3-HHB-1                                     （1-5）                    7% 3-HHB-O1                                  （1-5）                    4% 3-HBB-2                                       （1-6）                    5% 2-BB(F)B-3                                  （1-8）                    8% 2-BB(F)B-5                                （1-8） 8% 3-BB(F)B-5                                                                                      7% 3-BB(F,F)XB(F,F)-F （2-18） 12% 3-BB(F)B(F,F)XB(F,F)-F （2-29） 3% 4-BB(F)B(F,F)XB(F,F)-F                   6% 3-BB(F,F) 13% NI=90.7℃; Tc＜-20℃; η=34.0 mPa·s; Δn=0.170; Δε=8.6; Vth=1.88 V.

[Composition example 7] 3-HH-V                                                                                                                    8% 1-BB-3 5% 2-BB(F)B- 3 ( 1-13) 6% 5-HBB(F)B-3                                                                                    8% 3-BB(F)B(F,F)-F             (2 -15)           5% 3-BB(F,F)XB(F,F)-F               (2-18)                 18% 3-BB(F)B(F,F)XB(F,F)-F             (2 -29)           2% 4-BB(F)B(F,F)XB(F,F)-F                                                         6% 3-BB(F,F)XB(F)B(F,F)-F                       16% NI=86.8℃; 1.54 V; γ1=185.0 mPa·s.

[Composition example 8] 1-BB-3                                                                                                                      13% 2-BB(F)B-3 1-8 4% 1-BB( F)B-2V (1-8) 2% 2-BB(F)B-2V (1-8) 5% 3 -BB(F)B-2V                                                                                                                                                                                                                                      B-2                                                                          8% 5-HBB(F)B-3 (1-13) 7% 3-BB(2F,5F)B-3 (1) 8% 3-HHXB(F,F)-F （2-4） 2 % 3-BB (F,F) % NI=105.9℃; Tc＜-30℃; Δn=0.199; Δε=9.9; Vth=2.08 V; γ1=210.0 mPa·s.

[Composition example 9] 3-HH-V                                                                                                                     1-BB(F)B-2V 1% 1-8 3% 2-BB( F)B-2V (1-8) 6% 5-HBB(F)B-2 (1-13) 7% 5- HBB(F)B-3                                                             3% 3-HBB(F, F)-F                                    16% 3-BB(F,F)XB(F,F)-F （2-18） 21% 3-HHBB(F,F)-F （2-19） 3% 3-BB(F)B( F,F)XB(F,F)-F (2-29) 3% 4-BB(F)B(F,F)XB(F,F)-F (2-29) 11% 5-BB( F)B(F,F)XB(F,F)-F (2-29) 8% NI=91.3℃; Tc＜-40℃; η=31.7 mPa·s; Δn=0.160; Δε=13.9; Vth=1.41 V; γ1=123.0 mPa·s.

[Composition example 10] 3-HH-V                                                                                                      4.5% V-HHB-1 （1-5） 12% V-HBB-2 (1- 6) 4% 2-BB(F)B-3 （1-8） 3% 2-BB(F)B-5 (1-8) 2% 1-BB(F)B-2V (1-8)7% 2-BB(F)B-2V                                                                  4% 3-BB(F)B(F,F)-CF3 （2 -16)           4% 3-BB(F,F)XB(F,F)-F               (2-18)                 7.5% 4-GB(F)B(F,F)XB(F,F)-F        (2 -27)           2% 3-BB(F)B(F,F)XB(F,F)-F                                                                3% 4-BB(F)B(F,F)XB(F,F)-F (2-29) 6% NI=85.1℃; Tc＜-20℃; η=19.4 mPa·s; Δn=0.150 ; Δε=5.1; Vth=2.13 V; γ1=56.0 mPa·s.

[Composition example 11] 3-HH-V                                                                                                                           1-BB(F)B-2V 1% 1-8 3% 2-BB( F)B-2V (1-8) 6% 5-HBB(F)B-2 (1-13) 7% 5- HBB(F)B-3                                                             3% 3-HBB(F, F)-F (2-8) 16% 3-GB(F,F)XB(F,F)-F （2-14） 2% 3-BB(F,F)XB(F,F)-F （2-18） 1 9% 3- HHBB(F,F)-F (2-19) 3% 3-HBBXB(F,F)-F (2-23) 2% 3-BB( F)B(F,F)XB(F,F) -F                                     3% 4-BB(F)                                                                    9% 5-BB(F)B(F,F)XB(F,F)-F (2-29) 8% NI=92.4℃; Tc＜-20℃; η=31.2 mPa·s; Δn=0.159 ; Δε=13.7; Vth=1.51 V.

[Composition example 12] 3-HH-V                                                                                                  5.5% 2-BB(F)B-3 （1-8） 9% 2-BB( F)B-5                                                                                                  0% 1-BB(F)B-2V (1-8) 3% 2-BB(F) B-2V (1-8) 7% 3-BB(F)B-2V                                                                                               2% 2-HB(F)BH-3 （1-12） 2% 5-HBB( F)B-2 (1-13) 3% 5-HBB(F)B-3 (1-13) 5% 3-BB (F,F)XB(F,F)-F          (2-18)                15% 3-BB(F,F)XB(F)B(F,F)-F (2-30) 3% NI=97.8℃; ;Δε=3.8.

[Composition example 13] 3-HH-V                                                                                                                          10% V-HHB-1 1-5 8% 1-BB(F)B- 2v F)B(F,F)-F (2-15) 12% 3-BB(F ,F)XB(F,F)-F (2-18) 5% NI=70.5℃; Tc＜-20℃; η=9.2 mPa·s; Δn=0.111; Δε=2.5; Vth=2.48 V; γ1=35.0 mPa·s.

[Composition example 14] 3-HH-V                                                                                                                            5% 3-HHB-1 1-5 5% 1-BB(F)B- 2v F)B-2V (1-8) 4% 3-HHB(F,F)-F (2-2) 9% 3-BB(F)B(F,F)-F                                                                     2% 3-BB( F)B(F,F)XB(F,F)-F (2-29) 5% 4-BB(F)B(F,F)XB(F,F)-F (2-29) 4% NI=75.8℃; Tc＜-30℃; Δn=0.115; Δε=4.2; Vth=2.02 V; γ1=40.2 mPa·s.

[Composition example 15] 1-BB-3                                                                                                      7% 3-HBB-2 （1-6） 8% 5-B(F)BB- " % 3-BB(2F,3F)-O2                                         12% 5-BB(2F, 3F)- O2                               (3-6)  12% 3-HDhB(2F,3F)-O2 （3-13） 9% 3-dhBB(2F,3F)-O2 （3-16） 20% NI=90.3℃; Tc＜-20℃; η=47.7 mPa·s; Δn=0.193; Δε=-3.1.

[組成物例16] 1-BB-3                                   （1-3）                    4% 3-HBB-2                                （1-6）                    8% V-HBB-2                                （1-6）                    9% 5-B(F)BB- 2                                                                           9% 3-HB(2F,3F)-O2 (3-1) 8% 2-BB(2F,3F)- O2                                                                                                  6% 3-BB(2F,3F)-O2                                   10% 5-BB(2F, 3F)-O2                                      9% 3-HHB(2F,3F)-O2 （3-8 )                                                                                                                                                                 not not not not have been )                     8% 3-dhBB(2F,3F)-O2                                                           16)                        10% NI=90.7℃; Tc＜-20℃; η=40.0 mPa·s; Δn=0.181; Δε=-3.5.

[Composition Example 17] 3-HH-V                                  （1-1）                      9% 1-BB-3                                       （1-3）                        4% 1-BB-5                                       （1-3）                    12% 3-HBB-2                                     （1-6）                      6% 5-B(F)BB-2                                （1-7）                      11% 5-B(F)BB-3                                （1-7）                      11% 3-H1OB(2F,3F)-O2                    （3-3）  7% 3-BB(2F,3F)-O2 （3-6） 13% 2-HH1OB(2F,3F)-O2 （3-10） 13% 3-HH1OB(2F,3F)-O2 （3-10） 14% NI=75.0℃; Tc＜-20℃; η=21.1 mPa·s; Δn=0.150; Δε=-3.3; γ1 =153.0 mPa·s.

[Composition Example 18] 3-HBB-2                                   （1-6）                      9% 5-HBB(F)B-2                             （1-13）                     13% 3-BB(2F,5F)B-3                         （1）                       7% 3-HHXB(F,F)-F                          （2-4）                      1% 2-BB-C                                     （2-37）                    15% 5-BB-C                                     （2-37） 10% 2-BEB(F)-C （2-38） 5% 2-HHB(F)-C （ 2-39) 10% 3-HHB(F)-C 15% NI=114.2℃; Tc＜-20℃; η=54.0 mPa·s; Δn =0.202; Δε=16.1; Vth=1.52 V.

[Composition Example 19] 1-BB(F)B-2V                            （1-8）                     2% 2-BB(F)B-2V                             （1-8）                    2% 3-BB(F)B-2V                             （1-8）                    2% 3-HB-C                                   （2-36）                    4% 1V2-BEB(F,F)-C                          （2-38）                     19% 2-HHB-C                                   （2-39）                    5% 3-HHB-C                                    （2-39） 5% 2-HHB(F)-C (2-39) 2% 1-BTB-3 (11-1) 4% 2-BTB-1 （11-1） 8% 2-BTB-O1 （11-1） 11% 3-H2BTB-2 （11-2） 4% 3-H2BTB-3 （1 1-2) 4% 3-H2BTB-4 （11-2） 3-H2BTB-4 4% 3-HB(F)TB-2 (11-3) 8% 3-HB(F)TB-3 (11-3) 8% 3-HB(F)TB-4 (11-3) 8% NI=102.5℃; η=32.2 mPa·s; Δn=0.226; Δε=15.0; Vth=1.63 V.

[Composition Example 20] 2-PyBH-3                                  （1-14）                    7% 2-BEB-C                                     （2-38）                  12% 3-BEB-C                                     （2-38）                  4% 3-PyBB-F                                     （2）                      15% 4-BTB-O2 (11-1) 10% 5-BTB-O1 (11-1) 10% 3-HB(F)TB-2 （11-3） 8% 3-HB(F)TB-3 （11-3）​ 7% NI=89.3℃; Tc＜-20℃; η=37.8 mPa·s; Δn=0.230; Δε=12.6; Vth=1.50 V.

[Composition example 21] 3-HH-V                                                                                                                                                                                                                                                                                                         B-3           (1)                                                                                                                                                                    ,3F)-O2 (3-6) 8% V2-BB(2F,3F) -O2 (3-6) 8% 3-HDhB(2F,3F)-O2 (3-13) 4% 2-HBB(2F,3F)-O2 (3 -14) 3% 3-HBB(2F,3F)- O2                   （3-14）                  8% 4-HBB(2F,3F)-O2                   （3-14）                  5% 5-HBB(2F,3F)-O2                   （3-14）                  4% 3-dhBB(2F,3F) -O2 (3-16) 8% 3-HB(2F)B(2F,3F)-O2 (3-18) 8% NI=84.7℃; Tc＜-30℃; Δn=0.151; Δε=-4.1; γ1=141.0 mPa·s.

[Composition Example 22] 3-HH-V                                  （1-1）                      10% 1-BB-3                                      （1-3）                        4% 3-HBB-2                                   （1-6）                        5% V-HBB-2                                   （1-6）                      10% 5-B(F)BB-2                                  （1-7）                          10% 3-BB(2F,5F)B-3                           （1）                       5% 3-HB(2F,3F)-O2                         （3-1）                 2.5% 2-BB(2F,3F)-O2                     （3-6）                    8% 3-BB(2F,3F)-O2                     （3-6）                    6% V2-BB(2F,3F)-O2                   （3-6）                    8% 2-HBB(2F,3F)-O2                   （3-14）                  3% 3-HBB(2F,3F)-O2                   （3-14）                  8% 4-HBB(2F,3F)-O2                  （3-14）                 5% 3-dhBB(2F,3F)-O2 (3-16) 8% 3-HB(2F)B(2F,3F)-O2 (3-18) 7.5% NI=86.6℃; Tc＜-30℃; Δn=0.171; Δε=-3.2; γ1=150.0 mPa·s.

[Composition Example 23] 3-HH-V                                  （1-1）                      10% 1-BB-3                                       （1-3）                    4% 3-HBB-2                                    （1-6）                    5% V-HBB-2                                    （1-6）                    10% 5-B(F)BB-2                                （1-7）                      10% 3-BB(2F,5F)B-3                           （1）                       5% 3-HB(2F,3F)-O2                         （3-1）                   2.5% 2-BB(2F,3F)-O2                                       8% 3-BB(2F, 3F)                6% V2-BB(2F,3F)-O2 （3-6） 8% 2-HBB(2F,3F)-O2 （3-14） 3% 3-HBB(2F,3F)-O2 （3-14） 8% 4-HBB(2F,3F)-O2 （3-14） 5% 3-HB(2F)B(2F,3F)-O2 (3-18) 7.5% 2-BB(2F,3F)B-3 (3-19) 4 % 2O-DBTF2-O4 (3-34) 4% NI=82.3℃; Tc＜-20℃; Δn=0.175; Δε=-3.3; γ1=145.2 mPa·s.

[組成物例24] 3-HH-V                                  （1-1）                    16.5% 1-BB-3                                   （1-3）                    5.5% 2-BB(F)B-3                            （1-8）                    9% 2-BB( F)B-5                                                                            10% 1-BB(F)B-2V (1-8) 5% 2-BB(F) B-2V (1-8) 7% 3-BB(F)B-2V                                                                                                      5% 5-HBB(F)B-3 (1-13) 5% 3-BB(2F,5F)B-3 (1) 5% 3-BB(F,F)XB(F,F)-F (2-18) 15 % 3-BB(F,F)XB(F )B(F,F)-F (2-30) 3% NI=100.9℃；Tc＜-20℃；η=23.9 mPa·s；Δn=0.201；Δε=3.9. [Industrial Availability]

The liquid crystal composition of the present invention can be used in the viewing angle switching layer of the viewing angle adjustment element. The viewing angle adjustment element and the display device using the composition have excellent viewing angle adjustment function and can switch between wide viewing angle and narrow viewing angle well.

1: Liquid crystal display device 10: Viewing angle adjustment element 11: Viewing angle switching layer 11m, 11m': Liquid crystal molecules 11a, 11a': Molecular long axis 12a: First transparent electrode 12b: Second transparent electrode 13a: First light-transmitting substrate 13b: Second light-transmitting substrate 20: Liquid crystal display element 30: Backlight 41: First polarizing plate 41a: Transmission axis of first polarizing plate 42: Second polarizing plate 42a: Transmission axis of second polarizing plate 43: Third polarizing plate 43a: Transmission axis of third polarizing plate 50a: Front direction of liquid crystal display device 50b, 50c: Directions with specified angles Ra, Rb: Rubbing directions

FIG1 is a schematic cross-sectional view showing the structure of an example of a liquid crystal display device in one embodiment of the present invention. FIG2 is an exploded perspective view of the liquid crystal display device shown in FIG1. FIG3 is a schematic cross-sectional view showing the structure of an example of a liquid crystal display device in another embodiment of the present invention. FIG4 is an exploded perspective view of the liquid crystal display device shown in FIG3.

1: LCD display device

10: View angle adjustment element

11: View switching layer

11m: Liquid crystal molecules

11a: Major axis of molecule

12a: first transparent electrode

12b: Second transparent electrode

13a: first light-transmitting substrate

13b: Second light-transmitting substrate

20: Liquid crystal display element

30: Backlight

41: First polarizing plate

41a: Transmission axis of the first polarizer

42: Second polarizing plate

42a: Transmission axis of the second polarizer

43: Third polarizing plate

43a: Transmission axis of the third polarizing plate

50a: Front direction of the LCD device

50b, 50c: Directions with specified angles

Claims (9)

A liquid crystal composition for a viewing angle adjusting element, having positive dielectric anisotropy, comprising at least one compound selected from the compounds represented by formula (1) as component A; and at least one compound selected from the compounds represented by formula (2) as component B, wherein based on the mass of the liquid crystal composition, the total proportion of the compound represented by formula (1-3), the compound represented by formula (1-6), the compound represented by formula (1-7), the compound represented by formula (1-8), the compound represented by formula (1-9), the compound represented by formula (1-12) and the compound represented by formula (1-13) is 20 mass% or more, and the proportion of the component B is in the range of 5 mass% to 80 mass%,

In formula (1), formula (1-3), formula (1-6), formula (1-7), formula (1-8), formula (1-9), formula (1-12) and formula (1-13), R ^1a and R ^1b are alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyl having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; ring A ¹ and ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Z ¹ is a single bond, ethylene, vinylene, methyleneoxy, or carbonyloxy; a ¹ is 1, 2, or 3; in formula (2), R wherein ^R is 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; wherein Ring A 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; wherein ^Z is a single bond, ethylene, ethenylene, carbonyloxy, or difluoromethyleneoxy; wherein ^X is hydrogen or fluorine; wherein Y is a ...-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; wherein X is a ^1,4- cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4 ^a2 is fluorine, chlorine, cyano, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine; ^a2 is 1, 2, 3 or 4. The liquid crystal composition for viewing angle adjustment element as described in claim 1, wherein the proportion of component A is in the range of 20 mass % to 90 mass %. The liquid crystal composition for a viewing angle adjusting element according to claim 1 contains at least one compound selected from the group consisting of compounds represented by formula (2-1) to formula (2-39) as the component B,

In formula (2-1) to formula (2-39), R ² is 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; and X ^2a and X ^2b are hydrogen or fluorine. The liquid crystal composition for a viewing angle adjusting element according to claim 1 contains at least one compound selected from the group consisting of compounds represented by formula (3) as component C,

In formula (3), R ^3a and R ^3b are hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms; Ring A ³ and Ring C ³ are 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine or chlorine, naphthalene-2,6-diyl, naphthalene-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine, chromane-2,6-diyl, or chromane-2,6-diyl in which at least one hydrogen atom is substituted with fluorine or chlorine; Ring B ^Z3 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 1,1,6,7-tetrafluoroindan-2,5-diyl; ^Z3a and ^Z3b are a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; ^a3 is 0, 1, 2, or 3, ^b3 is 0 or 1; and the sum of ^a3 and ^b3 is 3 or less. The liquid crystal composition for a viewing angle adjusting element according to claim 4 contains at least one compound selected from the group consisting of compounds represented by formula (3-1) to formula (3-35) as the component C,

In formula (3-1) to formula (3-35), R ^3a and R ^3b are hydrogen, 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 alkenyloxy group having 2 to 12 carbon atoms. The liquid crystal composition for viewing angle adjustment element as described in claim 4, wherein the proportion of component C is in the range of 5 mass % to 70 mass % based on the mass of the liquid crystal composition. A viewing angle adjustment element, comprising: a viewing angle switching layer; and a pair of electrodes for applying a voltage to the viewing angle switching layer, wherein the viewing angle switching layer comprises a liquid crystal composition for a viewing angle adjustment element, wherein the liquid crystal composition for a viewing angle adjustment element has positive dielectric anisotropy and contains at least one compound selected from the compounds represented by formula (1) as component A, and at least one compound selected from the compounds represented by formula (2) as component B, wherein based on the The mass of the liquid crystal composition is such that the total proportion of the compound represented by formula (1-3), the compound represented by formula (1-6), the compound represented by formula (1-7), the compound represented by formula (1-8), the compound represented by formula (1-9), the compound represented by formula (1-12) and the compound represented by formula (1-13) is 20 mass % or more, and the proportion of component B is in the range of 5 mass % to 80 mass %,

In formula (1), formula (1-3), formula (1-6), formula (1-7), formula (1-8), formula (1-9), formula (1-12) and formula (1-13), R ^1a and R ^1b are alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyl having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted with fluorine or chlorine; ring A ¹ and ring B ¹ are 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidine-2,5-diyl; Z ¹ is a single bond, ethylene, ethenylene, methyleneoxy, or carbonyloxy; a ¹ is 1, 2, or 3; in formula (2), R wherein ^R is 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; wherein Ring A 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; wherein ^Z is a single bond, ethylene, ethenylene, carbonyloxy, or difluoromethyleneoxy; wherein ^X is hydrogen or fluorine; wherein Y is a ...-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; wherein X is a ^1,4- cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6-difluoro-1,4 ^a2 is fluorine, chlorine, cyano, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, an alkoxy group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine, or an alkenyloxy group having 2 to 12 carbon atoms in which at least one hydrogen atom is substituted by fluorine or chlorine; ^a2 is 1, 2, 3 or 4. A display device capable of adjusting the viewing angle, comprising a viewing angle adjustment element as described in claim 7. A liquid crystal display device capable of adjusting the viewing angle, comprising a viewing angle adjustment element as described in claim 7.