Liquid crystal composition for use in an element for controlling the phase of an electromagnetic wave signal

Abstract

To provide a liquid crystal composition that is required as a material used in an element for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz, which has a high upper limit temperature of a nematic phase, a low lower limit temperature of a nematic phase, large dielectric anisotropy and a small tanδ in a frequency region where the phase control of an electromagnetic wave signal is performed, and stability against heat, and which has well-balanced characteristics.SOLUTION: A liquid crystal composition is used in an element for phase control of an electromagnetic wave signal having any frequency from 1 GHz to 10 THz, the liquid crystal composition containing at least one compound selected from the group of compounds represented by Formula (1) as a first component.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an element used for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz, and a liquid crystal composition used in the element. The composition has a nematic phase and positive dielectric anisotropy. [Background technology]

[0002] Liquid crystal compositions are widely used in display applications, but as a new application of liquid crystal compositions, applications to high frequency technologies such as antennas for transmitting and receiving electromagnetic waves are attracting attention.

[0003] Specifically, elements used for phase control of electromagnetic signals with frequencies of 1 GHz to 10 THz include millimeter wave band / microwave band antennas, infrared laser elements, etc. Various types of these elements are being considered, and a method using a liquid crystal composition, which is thought to be less prone to failure because it has no mechanical moving parts, has attracted attention.

[0004] A liquid crystal composition having dielectric anisotropy has different dielectric constants in the perpendicular and horizontal directions relative to the alignment direction of the liquid crystal composition at frequencies (several hundred kHz to several hundred MHz or less) lower than the frequency (relaxation frequency) at which the alignment polarization relaxes. Even at frequencies higher than the relaxation frequency, i.e., in the range of microwaves to terahertz waves (up to 10 THz), the value is small, but a difference in dielectric constant between the vertical and horizontal directions relative to the alignment direction of the liquid crystal composition is observed, and there is dielectric anisotropy. The value is almost constant in the range of microwaves to terahertz waves (up to 10 THz) (Non-Patent Document 1). Therefore, the liquid crystal composition can change its dielectric constant in one direction by changing the alignment direction of the molecules in response to an external field (electric field).

[0005] By utilizing this property, the molecular orientation of the liquid crystal composition can be changed in response to an external electric field, thereby changing the dielectric constant. For example, it will be possible to realize a microwave device that can electrically control the transmission characteristics of a high-frequency transmission line from the outside. Examples of such devices that have been reported include a voltage-controlled millimeter-wave band variable phase shifter in which a waveguide is filled with a nematic liquid crystal composition, and a wideband variable phase shifter in the microwave and millimeter-wave bands that uses a nematic liquid crystal composition as the dielectric substrate of a microstrip line (Patent Documents 1 and 2).

[0006] In recent years, research on metamaterial technology, which exhibits behavior not seen in natural materials with respect to electromagnetic waves including light, has been progressing. Due to its characteristics, it has been applied to technical fields such as high-frequency devices, microwave devices, and antennas, and various electromagnetic wave control elements have been devised. As a capacitance control material for transmission lines using metamaterials, the use of liquid crystal compositions that can change the molecular orientation in response to an external electric field, as in phase control, and can change the dielectric constant, has also been considered.

[0007] It is desirable for an element used for such phase control of an electromagnetic wave signal to have characteristics such as high gain and low loss. Considering the phase control of a high frequency signal, the characteristics required for a liquid crystal composition are a large dielectric anisotropy that enables wide phase control in the frequency range used for phase control, and a small dielectric loss tangent (tan δ) that is proportional to the absorbed energy of the electromagnetic wave signal of the liquid crystal composition (Non-Patent Document 1).

[0008] Since liquid crystal compositions are dielectrics, they generate polarization (dielectric polarization) in response to an external field (electric field). The dielectric constant is a physical quantity that indicates the response of a dielectric to an electric field, and the magnitude of the dielectric constant is related to the dielectric polarization. The mechanisms by which dielectric polarization occurs can be broadly divided into three: electronic polarization, ionic polarization, and orientation polarization. Orientation polarization is polarization associated with the orientation of the dipole moment, and as shown above, it relaxes and becomes smaller at frequencies from several hundred kHz to several hundred MHz. As a result, at high frequencies (in the range of microwaves to terahertz waves (up to 10 THz)), only electronic polarization and ionic polarization are involved in dielectric polarization. In lossless dielectrics, the dielectric constant (ε) and refractive index (n) are related to each other as follows: ε=n 2 If the ionic polarization of the liquid crystal composition is considered to be small, it is considered that the larger the refractive index anisotropy (Δn) in visible light caused by electronic polarization, the larger the dielectric anisotropy (Δε) in the high frequency range will be (Non-Patent Document 2). Therefore, it is preferable for the liquid crystal composition to have a large refractive index anisotropy.

[0009] In order to realize the switching characteristics and high energy efficiency of the element, a low driving voltage is desirable, and therefore it is preferable for the liquid crystal composition to have a large dielectric anisotropy even at low frequencies (frequencies lower than the relaxation frequency).

[0010] In addition, elements used for phase control of electromagnetic wave signals are required to have a wide usable temperature range and a short response time, and the liquid crystal composition is required to have such properties as a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, thermal stability, and low viscosity.

[0011] Conventional liquid crystal compositions used in such devices are disclosed in Patent Documents 3 and 4 listed below. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] International Publication No. 2017 / 201515 [Patent Document 2] International Publication No. 2017 / 208996 [Patent Document 3] JP 2004-285085 A [Patent Document 4] JP 2011-74074 A [Non-patent literature]

[0013] [Non-Patent Document 1] EKISHO, Vol. 23(No. 1), (2019), pp. 51-55. [Non-Patent Document 2] Theory of Dielectric Phenomena, Institute of Electrical Engineers of Japan, Ohmsha Co., Ltd., July 25, 1973, pp. 92-95 Summary of the Invention [Problem to be solved by the invention]

[0014] As a material for an element used for phase control of an electromagnetic wave signal, a liquid crystal composition is required to have a high upper limit temperature of the nematic phase and a low lower limit temperature of the nematic phase, while having a large dielectric anisotropy (large refractive index anisotropy) in the frequency range where phase control of the electromagnetic wave signal is performed, a small tan δ, and a large dielectric anisotropy at low frequencies for reducing the driving voltage, and more preferably, to have a small viscosity, a large resistivity in the driving frequency range, and thermal stability.

[0015] However, liquid crystal compositions used in conventional display applications are insufficient in terms of characteristics for use in elements used for phase control of such electromagnetic signals, as they have high loss and / or insufficient phase shift, and are therefore insufficient for use in phase control of high frequency signals.

[0016] The development of liquid crystal materials for elements used in the phase control of electromagnetic signals is still in its infancy, and attempts are constantly being made to develop new compounds that allow the optimization of such elements in order to improve the properties of high frequency control.Specific liquid crystal media are then required for use as materials for elements used in electromagnetic wave control.

[0017] An object of the present invention is to provide a liquid crystal composition which satisfies the above-mentioned required characteristics and has an excellent balance of characteristics as a material for an element used for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz. [Means for solving the problem]

[0018] As a result of intensive research, the inventors have found that a liquid crystal composition containing a liquid crystal compound having a specific structure can solve the above problems, and have completed the present invention. That is, a liquid crystal composition used in an element for controlling the phase of an electromagnetic wave signal having a frequency of any one of 1 GHz to 10 THz, containing at least one compound selected from the group of compounds represented by formula (1) as a first component. TIFF0007673586000001.tif2097 In formula (1), R 1 is 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, 1 Non-adjacent -CH in 2 - may be replaced by -S-, hydrogen may be replaced by fluorine, Ring A 11 is a group selected from the group consisting of group (A) and group (B), TIFF0007673586000002.tif30107 In the group (A), non-adjacent -CH 2 - may be replaced by -O- or -S-, and in the radicals of group (B), at least one -CH= may be replaced by -N=; In the groups (A) and (B), at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms; Ring A 12 is 1,4-phenylene, at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbons, or cycloalkyl having 3 to 6 carbons; Z 11 is a single bond, -CH=CH-, or -C≡C-, and Z 12 is a single bond, -CH 2 CH 2 -, -CH=CH-, or -C≡C-; Z 12 One of them is -CH 2 CH 2 -, -CH=CH-, or -C≡C-, and R 1 If the hydrogen in is replaced by fluorine, Z 11 is -C≡C-, or ring A 11 When at least one hydrogen atom of Z is replaced by cyano, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms, 12 may all be single bonds, n 1 is 1, 2, or 3. Effect of the Invention

[0019] According to the present invention, it is possible to provide a liquid crystal composition which has a high upper limit temperature of a nematic phase and a low lower limit temperature of a nematic phase, while also having a large dielectric anisotropy in the frequency range where phase control of an electromagnetic wave signal is performed, a small tan δ, and a large dielectric anisotropy at low frequencies for reducing the driving voltage, and further (preferably) has a small viscosity, a large resistivity in the driving frequency range, and thermal stability, and an element using the liquid crystal composition of the present invention can exhibit excellent characteristics capable of controlling the phase of an electromagnetic wave signal over a wide temperature range. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The terms used in this specification are as follows. The terms "liquid crystal composition" and "electromagnetic wave control element" may be abbreviated to "composition" and "element", respectively. "Electromagnetic wave signal phase control element" is a general term for an electromagnetic wave signal phase control panel and an electromagnetic wave signal phase control module. "Liquid crystal compound" is a general term for compounds having a liquid crystal phase such as a nematic phase or a smectic phase, and compounds that do not have a liquid crystal phase but are mixed into a composition for the purpose of adjusting properties such as the temperature range, viscosity, and dielectric anisotropy of the nematic phase. This compound has a six-membered ring such as 1,4-cyclohexylene or 1,4-phenylene, and its molecules (liquid crystal molecules) are rod-like. "Polymerizable compound" is a compound added to a composition for the purpose of generating a polymer. Liquid crystal compounds having alkenyl are not classified as polymerizable compounds in this sense.

[0021] A liquid crystal composition is prepared by mixing a plurality of liquid crystal compounds, to which additives such as optically active compounds and polymerizable compounds are added as required. In the present specification, the ratio of the liquid crystal compound is expressed as a mass percentage (mass%) based on the mass of the liquid crystal composition not including the additive, even if an additive is added. The ratio of the additive is expressed as a mass percentage (mass%) based on the mass of the liquid crystal composition not including the additive. In other words, the ratio of the liquid crystal compound or the additive is calculated based on the total mass of the liquid crystal compound.

[0022] "The maximum temperature of a nematic phase" may be abbreviated as "maximum temperature". "The minimum temperature of a nematic phase" may be abbreviated as "minimum temperature". The expression "increasing the dielectric anisotropy" means that the value increases positively in the case of a composition having a positive dielectric anisotropy, and means that the value increases negatively in the case of a composition having a negative dielectric anisotropy.

[0023] TIFF0007673586000003.tif2269 The above compound (1z) is taken as an example. In formula (1z), the symbols α and β surrounded by a hexagon correspond to ring α and ring β, respectively, and represent rings such as six-membered rings and fused rings. 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. This rule applies to any two rings α when the subscript 'x' is greater than 2. This rule also applies to other symbols, such as the bond group Z. The diagonal line across one side of ring β represents that any hydrogen on ring β may be replaced with a substituent (-Sp-P). The subscript 'y' indicates the number of replaced substituents. When the subscript 'y' is 0, there is no such replacement. When the subscript 'y' is 2 or more, there are multiple substituents (-Sp-P) on ring β. In this case, the rule that "may be the same or different" also applies. This rule also applies when the symbol Ra is used for multiple compounds.

[0024] In formula (1z), for example, an expression such as "Ra and Rb are alkyl, alkoxy, or alkenyl" means that Ra and Rb are independently selected from the group of alkyl, alkoxy, and alkenyl. Here, the group represented by Ra and the group represented by Rb may be the same or different. This rule also applies when the symbol Ra is used in multiple compounds. This rule also applies when multiple Ra are used in one compound.

[0025] At least one compound selected from the compounds represented by formula (1z) may be abbreviated as "compound (1z)". "Compound (1z)" means 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 formulas. The expression "at least one compound selected from the compounds represented by formula (1z) and formula (2z)" means at least one compound selected from the group of compounds (1z) and compounds (2z).

[0026] The expression "at least one 'A'" means that the number of 'A' is arbitrary. The expression "at least one 'A' may be replaced with '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 be selected without restriction. "at least one -CH 2 - may be replaced by -O-. In this case, -CH 2 -CH 2 -CH 2 - is not adjacent to -CH 2 - is replaced with -O- to create -O-CH 2 However, adjacent -CH 2 - cannot be replaced by -O-. In this replacement, -OO-CH 2 This is because - (peroxide) is produced.

[0027] The alkyl of the liquid crystal compound is linear or branched, and does not include cyclic alkyl. Linear alkyl is more preferable than branched alkyl. The same applies to terminal groups such as alkoxy and alkenyl. The stereoconfiguration of 1,4-cyclohexylene is preferably trans rather than cis in order to increase the maximum temperature. 2-Fluoro-1,4-phenylene is asymmetric, so it exists in left-facing (L) and right-facing (R) configurations. TIFF0007673586000004.tif26130 The same applies to a divalent group such as tetrahydropyran-2,5-diyl. Note that preferred tetrahydropyran-2,5-diyl faces right (R) in order to increase the maximum temperature. The same applies to a bonding group such as carbonyloxy (-COO- or -OCO-).

[0028] The present invention includes the following items.

[0029] Item 1. A liquid crystal composition used in an element for controlling the phase of an electromagnetic wave signal having a frequency of any one of 1 GHz to 10 THz, comprising at least one compound selected from the group of compounds represented by formula (1) as a first component. TIFF0007673586000005.tif21102 In formula (1), R 1 is 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, 1 Non-adjacent -CH in 2 - may be replaced by -S-, hydrogen may be replaced by fluorine, Ring A 11 is a group selected from the group consisting of group (A) and group (B), TIFF0007673586000006.tif36125 In the group (A), non-adjacent -CH 2 - may be replaced by -O- or -S-; in the group (B), at least one -CH= may be replaced by -N=; in the groups (A) and (B), at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms; Ring A 12 is 1,4-phenylene, at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbons, or cycloalkyl having 3 to 6 carbons; Z 11 is a single bond, -CH=CH-, or -C≡C-, and Z 12 is a single bond, -CH 2 CH 2 -, -CH=CH-, or -C≡C-; Z 12 One of them is -CH 2 CH 2 -, -CH=CH-, or -C≡C-, and R 1 If the hydrogen in is replaced by fluorine, Z 11is -C≡C-, or ring A 11 When at least one hydrogen atom of Z is replaced by cyano, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms, 12 may all be single bonds, n 1 is 1, 2, or 3.

[0030] Item 2. The liquid crystal composition according to item 1, comprising, as a first component, at least one compound selected from the compounds represented by formulas (1-1) to (1-9): TIFF0007673586000007.tif211140 TIFF0007673586000008.tif99145 In these formulas, R 1 is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyloxy having 2 to 12 carbons, Y 11 , Y 12 and Y 13 is hydrogen, fluorine, methyl, ethyl or cycloalkyl having 3 to 6 carbon atoms; Y 14 is methyl, ethyl or cycloalkyl having 3 to 6 carbon atoms; Ring A 12 is 1,4-phenylene, and at least one hydrogen may be replaced by fluorine or alkyl having 1 to 5 carbon atoms.

[0031] Item 3. The liquid crystal composition according to item 1 or 2, wherein the proportion of the first component is in the range of 5% by mass to 60% by mass, based on the mass of the liquid crystal composition.

[0032] Item 4. The liquid crystal composition according to any one of items 1 to 3, further comprising at least one compound selected from the group of compounds represented by formula (2) as a second component: TIFF0007673586000009.tif34130 In formula (2), R21 and R 22 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, 21 and R 22 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that the O atoms are not directly bonded to each other; Ring A 2 is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2,6-benzothiophene, or 7-fluoro-2,6-benzothiophene; Z 21 and Z 22 is a single bond, -CH 2 CH 2 -, -CH=CH-, -C≡C-, -COO- or -C≡CC≡C-; Y 21 and Y 22 is hydrogen, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms; Y 23 , Y 24 and Y 25 is hydrogen or fluorine, while Y 24 and Y 25 is not simultaneously fluorine;n 2 is 0, 1, or 2.

[0033] Item 5. The liquid crystal composition according to item 4, comprising, as a second component, at least one compound selected from the group of compounds represented by formulas (2-1) to (2-21): TIFF0007673586000010.tif216125 TIFF0007673586000011.tif221130 In these formulas, R 21 and R 22 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, 21and R 22 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, or -C≡C-, provided that O atoms are not directly bonded to each other.

[0034] Item 6. The liquid crystal composition according to item 4 or 5, wherein a ratio of the second component is in the range of 40% by mass to 90% by mass.

[0035] Item 7. The liquid crystal composition according to any one of items 1 to 6, comprising, as a third component, at least one compound selected from the group of compounds represented by formula (3): TIFF0007673586000012.tif31118 In formula (3), R 3 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, 3 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that the O atoms are not directly bonded to each other and hydrogen may be replaced by fluorine; Ring A 31 is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; Ring A 32 is 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, or pyridine-2,5-diyl, pyrimidine-2,5-diyl; Z 31 and Z 32 is a single bond, -CH 2 CH 2-, -CH=CH-, -C≡C-, -COO- or -CF 2 O-;X 3 -F, -Cl, -CF 3 , -OCF 3 , -C≡C-CF 3 , -C≡C-OCF 3 , -CN, or -NCS;Y 31 , Y 32 and Y 33 is hydrogen or fluorine, but Y 31 and Y 32 is not simultaneously fluorine;n 3 is 1, 2, or 3.

[0036] Item 8. The liquid crystal composition according to item 7, comprising at least one compound selected from the group of compounds represented by formulas (3-1) to (3-28) as a third component: TIFF0007673586000013.tif254155 TIFF0007673586000014.tif247161 TIFF0007673586000015.tif221150 TIFF0007673586000016.tif143166 In these formulas, R 3 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, 3 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, or -C≡C-, provided that O atoms are not directly bonded to each other.

[0037] Item 9. The liquid crystal composition according to item 7 or 8, wherein a ratio of the third component is in the range of 5% by mass to 30% by mass.

[0038] Item 10. The liquid crystal composition according to any one of items 1 to 9, which has a refractive index anisotropy at 25° C. and a wavelength of 589 nm of 0.20 to 0.80.

[0039] Item 11. The liquid crystal composition according to any one of items 1 to 10, wherein the dielectric anisotropy at 25° C. at any frequency from 1.1 GHz to 10 THz is in the range of 0.40 to 2.0.

[0040] Item 12. The liquid crystal composition according to any one of items 1 to 11, comprising an optically active compound.

[0041] Item 13. The liquid crystal composition according to any one of items 1 to 12, further comprising a polymerizable compound.

[0042] Item 14. A device used for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz, comprising the liquid crystal composition according to any one of items 1 to 13.

[0043] The present invention also includes the following: (a) the above composition containing one compound, two compounds, or three or more compounds selected from additives such as optically active compounds, antioxidants, ultraviolet absorbers, quenchers, dyes, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, and polar compounds; (b) an AM element containing the above composition; (c) the above composition further containing a polymerizable compound, and a polymer supported alignment (PSA) type AM element containing the composition; (d) an element containing the above composition and having a PC, TN, STN, ECB, OCB, IPS, VA, FFS, or FPA mode; (e) a transmission type element containing the above composition; (f) use of the above composition as a composition having a nematic phase; (g) use of an optically active composition obtained by adding an optically active compound to the above composition.

[0044] The liquid crystal composition of the present invention has a large dielectric anisotropy and a small tan δ in the frequency range of electromagnetic signals from 1 GHz to 10 THz, and is therefore preferably used in devices relating to electromagnetic waves from 1 GHz to 10 THz, and further from 1 GHz to 50 GHz.

[0045] The composition of the present invention will be described in the following order. First, the constitution of the composition will be described. Second, the main properties of the component compounds and the main effects that these compounds have on the composition and the device will be described. Third, the combination of the component compounds in the composition, the preferred ratios, and the reasons therefor will be described. Fourth, the preferred forms of the component compounds will be described. Fifth, preferred component compounds will be shown. Sixth, additives that may be added to the composition will be described. Seventh, a method for synthesizing the component compounds will be described. Finally, the uses of the composition will be described.

[0046] First, the composition will be described. This composition contains a plurality of liquid crystal compounds. This composition may contain additives. The additives are optically active compounds, antioxidants, ultraviolet absorbers, quenchers, dyes, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, and the like. This composition is classified into composition (a) and composition (b) from the viewpoint of liquid crystal compounds. Composition (a) may further contain other liquid crystal compounds, additives, and the like in addition to the liquid crystal compounds selected from compound (1), compound (2), and compound (3). "Other liquid crystal compounds" are liquid crystal compounds different from compound (1), compound (2), and compound (3). Such compounds are mixed into the composition for the purpose of further adjusting the properties.

[0047] Composition (b) consists essentially of liquid crystal compounds selected from compound (1), compound (2) and compound (3). "Substantially" means that composition (b) may contain additives, but does not contain other liquid crystal compounds. Composition (b) has fewer components than composition (a). From the viewpoint of reducing costs, composition (b) is more preferable than composition (a). From the viewpoint of being able to further adjust the properties by mixing other liquid crystal compounds, composition (a) is more preferable than composition (b).

[0048] Secondly, the main characteristics of the component compounds and the main effects of the compounds on the composition and the device are explained. The main characteristics of the component compounds are summarized in Table 1 based on the effects of the present invention. In the symbols in Table 1, L means large or high, M means medium, and S means small or low. The symbols L, M, and S are classifications based on qualitative comparisons between the component compounds, and the symbol 0 (zero) means smaller than S.

[0049] Table 1. Characteristics of liquid crystal compounds TIFF0007673586000017.tif36125

[0050] The main effects of the component compounds are as follows: Compound (1) has the effect of increasing the dielectric anisotropy while increasing the refractive index anisotropy. The upper limit temperature and viscosity depend on the number of rings contained in the compound (n in formula (1)). 1 This can be adjusted by changing the number of rings (the number of rings). In other words, if the number of rings is increased, the maximum temperature increases, but the viscosity also increases, and the minimum temperature also tends to increase. On the other hand, if the number of rings is decreased, the maximum temperature does not increase, but the viscosity decreases, and the minimum temperature tends to decrease. Compound (2) has the effect of increasing the refractive index anisotropy while widening the temperature range of the nematic phase. 2 The relationship between the number of (a) and the maximum temperature, the minimum temperature, and the viscosity tends to be similar to that of compound (1); however, compound (2) tends to have a greater effect of increasing the maximum temperature, decreasing the minimum temperature, and decreasing the viscosity than compound (1). Compound (3) has the effect of increasing the dielectric anisotropy. In the present invention, compound (1) increases the dielectric anisotropy, but in order to achieve high switching characteristics and high energy efficiency, a large dielectric anisotropy is preferable. When the dielectric anisotropy is insufficient when only compound (1) is used, compound (3) is used to compensate.

[0051] Thirdly, the combination of components in the composition, the preferred ratio of the component compounds and the basis thereof will be explained. A preferred combination of components in the composition is compound (1) + compound (2) or compound (1) + compound (2) + compound (3), and a particularly preferred combination is compound (1) + compound (2), which can further increase the refractive index anisotropy and dielectric anisotropy.

[0052] A preferred ratio of compound (1) is in the range of about 5% by mass to about 60% by mass in order to increase the dielectric anisotropy and the refractive index anisotropy while suppressing an increase in the minimum temperature. A more preferred ratio is in the range of about 10% by mass to about 50% by mass. A particularly preferred ratio is in the range of about 10% by mass to about 40% by mass.

[0053] A preferred ratio of compound (2) is in the range of about 40% by mass to about 90% by mass in order to increase the refractive index anisotropy while expanding the temperature range of the nematic phase. A more preferred ratio is in the range of about 50% by mass to about 90% by mass. A particularly preferred ratio is in the range of about 60% by mass to about 90% by mass.

[0054] A preferred ratio of compound (3) is in the range of about 5% by mass to about 30% by mass in order to increase the dielectric anisotropy and the refractive index anisotropy while suppressing an increase in the minimum temperature. A more preferred ratio is in the range of about 5% by mass to about 25% by mass. A particularly preferred ratio is in the range of about 5% by mass to about 20% by mass.

[0055] Fourthly, preferred forms of the component compounds will be described. In the formulas (1), (2), and (3), R 1 is alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyloxy having 2 to 12 carbon atoms; R 1 Non-adjacent -CH in 2 - may be replaced by -O- or -S-, and hydrogen may be replaced by fluorine. 1 is an alkyl group having 1 to 12 carbon atoms for increasing stability against light or heat.

[0056] R 21 and R 22 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; R 21 and R 22 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that the O atoms are not directly bonded to each other. 21 and R 22 is an alkyl group having 1 to 12 carbon atoms for increasing stability against light or heat.

[0057] R 3 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; R 3 Non-adjacent -CH in 2 - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that the O atoms are not directly bonded to each other, and hydrogen may be replaced by fluorine. 3 is an alkyl group having 1 to 12 carbon atoms for increasing stability against light or heat.

[0058] Preferred alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl. More preferred alkyl groups are methyl, ethyl, propyl, butyl, and pentyl for decreasing the viscosity.

[0059] Preferred alkoxy is methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, or heptyloxy. More preferred alkoxy is methoxy or ethoxy for decreasing the viscosity.

[0060] Preferred alkenyls 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. More preferred alkenyls are vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl to reduce viscosity. The preferred configuration of -CH=CH- in these alkenyls depends on the position of the double bond. In order to reduce viscosity, trans is preferred in alkenyls such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl, and 3-hexenyl. Cis is preferred in alkenyls such as 2-butenyl, 2-pentenyl, and 2-hexenyl.

[0061] Preferred alkenyloxy is vinyloxy, allyloxy, 3-butenyloxy, 3-pentenyloxy, or 4-pentenyloxy. In order to decrease the viscosity, more preferred alkenyloxy is allyloxy or 3-butenyloxy.

[0062] Ring A 11 is a group selected from the group consisting of group (A) and group (B), TIFF0007673586000018.tif36125 In the group (A), non-adjacent -CH 2 - may be replaced by -O- and / or -S-; in the groups in group (B), at least one -CH= may be replaced by -N=; and in the groups in groups (A) and (B), at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms.

[0063] Ring A 11 Examples of the groups are those represented by the following formulae (I) to (XXII). TIFF0007673586000019.tif173145 In these, hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms.

[0064] Preferred Ring A 11 In order to increase the refractive index anisotropy and compatibility, TIFF0007673586000020.tif2321 and Y 11 , Y 12 and Y 13 is hydrogen, fluorine, methyl, ethyl or cycloalkyl having 3 to 6 carbon atoms. Preferred Y 11 , Y 12 and Y 13 is hydrogen for increasing the refractive index anisotropy, and is fluorine, methyl, ethyl, or cyclopropane for increasing the compatibility.

[0065] Ring A 12 is 1,4-phenylene, and at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms. 12 is 1,4-phenylene in order to increase the refractive index anisotropy and to increase the dielectric anisotropy, and at least one hydrogen is replaced by fluorine.

[0066] Ring A 2 is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2,6-benzothiophene, or 7-fluoro-2,6-benzothiophene. 2 is 1,4-cyclohexylene to decrease the viscosity, or 1,4-phenylene to increase the refractive index anisotropy.

[0067] Ring A 31is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl. 31 is 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,6-difluoro-1,4-phenylene in order to increase the refractive index anisotropy.

[0068] Ring A 32 is 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, or pyrimidine-2,5-diyl. 32 is 1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,6-difluoro-1,4-phenylene in order to increase the refractive index anisotropy.

[0069] Tetrahydropyran-2,5-diyl is TIFF0007673586000021.tif1323 or TIFF0007673586000022.tif1322 and preferably TIFF0007673586000023.tif1322 It is.

[0070] Z 11 is a single bond, -CH=CH-, or -C≡C-, and Z 12 is a single bond, -CH 2 CH 2 -, -CH=CH-, or -C≡C-, and there are multiple Z 12 may be the same or different, but Z 12 One of them is -CH 2 CH 2-, -CH=CH-, or -C≡C-, and R 1 If the hydrogen in is replaced by fluorine, Z 11 is -C≡C-, or ring A 11 When at least one hydrogen atom of Z is replaced by cyano, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms, 12 may all be single bonds. 11 and Z 12 In order to increase the refractive index anisotropy, Z is preferably -CH=CH- or -C≡C-. 11 and Z 12 is -C≡C-.

[0071] Z 21 and Z 22 is a single bond, -CH 2 CH 2 -, -CH=CH-, -C≡C-, -COO- or -C≡CC≡C-. Preferred Z 21 and Z 22 is -C≡C- or -C≡CC≡C- in order to increase the refractive index anisotropy.

[0072] Z 31 and Z 32 is a single bond, -CH 2 CH 2 -, -CH=CH-, -C≡C-, -COO- or -CF 2 O-. Preferred Z 31 and Z 32 In order to increase the dielectric anisotropy, -CF 2 It is O-.

[0073] In carbonyloxy, -COO- is preferred to -OCO-. In difluoromethyleneoxy, -CF 2 O-OCF 2 - is preferable.

[0074] X 3 -F, -Cl, -CF 3 , -OCF 3 , -C≡C-CF 3, -C≡C-OCF 3 , -CN, or -NCS. 3 In order to increase the dielectric anisotropy, -F, -OCF 3 , -CN or -NCS, and considering stability, -F or -OCF 3 In order to increase the refractive index anisotropy while increasing the dielectric anisotropy, -C≡C-CF 3 , -C≡C-OCF 3 It is.

[0075] Y 21 and Y 22 is hydrogen, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms. 21 and Y 22 is fluorine for increasing the dielectric anisotropy, and is ethyl or cyclopropyl for increasing the compatibility.

[0076] Y 23 , Y 24 and Y 25 are hydrogen, fluorine, but Y 24 and Y 25 and cannot be fluorine at the same time. 23 , Y 24 and Y 25 is fluorine to decrease the minimum temperature.

[0077] Y 31 , Y 32 and Y 33 is hydrogen or fluorine, while Y 31 and Y 32 and cannot be fluorine at the same time. 31 is hydrogen, and the preferred Y 32 and Y 33 is fluorine to increase the dielectric anisotropy.

[0078] n 1 is 1, 2, or 3. 1is 1 when priority is given to decreasing the viscosity and the minimum temperature, and is 3 when priority is given to increasing the maximum temperature and the refractive index anisotropy. In the present invention, it is more preferable that it is 1 in order to combine with compound (2) having a high maximum temperature in order to increase the refractive index anisotropy.

[0079] n 2 is 0, 1 or 2. 2 is 0 when priority is given to lowering the viscosity, and is 1 or 2 when priority is given to increasing the maximum temperature or the refractive index anisotropy. In the present invention, it is more preferable that it is 0 or 1 in order to adjust the temperature range of the nematic phase while increasing the refractive index anisotropy.

[0080] n 3 is 1, 2 or 3. 3 is 1 when priority is given to lowering the viscosity, and is 2 or 3 when priority is given to increasing the maximum temperature and the refractive index anisotropy. In the present invention, it is more preferable that the value is 2 in order to increase the maximum temperature and increase the refractive index anisotropy without increasing the minimum temperature.

[0081] Fifth, preferred component compounds are shown below. Preferred compound (1) is compound (1-1) to compound (1-9) described in item 2. In these compounds, at least one of the first components is preferably compound (1-1), compound (1-2), or compound (1-3).

[0082] Preferred compounds (2) are compounds (2-1) to (2-21) described in item 5. In these compounds, at least one of the second components is preferably compound (2-2), compound (2-3), compound (2-4), compound (2-7), compound (2-9), compound (2-11), compound (2-12), compound (2-13), compound (2-17) or compound (2-19).

[0083] Preferred compound (3) is compound (3-1) to compound (3-28) described in item 8. At least one of the third components is preferably compound (3-1), compound (3-2), compound (3-3), compound (3-7), compound (3-9), compound (3-10), compound (3-11), compound (3-12) or compound (3-14).

[0084] Sixth, additives that may be added to the composition will be described. Such additives include optically active compounds, antioxidants, ultraviolet absorbers, quenchers, defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, etc. The optically active compounds are added to the composition for the purpose of inducing a helical structure of the liquid crystal molecules to give a twist angle. Examples of such compounds are compounds (4-1) to (4-5). The preferred ratio of the optically active compounds is about 5% by mass or less. More preferred ratios are in the range of about 0.01% by mass to about 2% by mass.

[0085] TIFF0007673586000024.tif163117

[0086] In order to prevent a decrease in resistivity due to heating in the atmosphere, or in order to maintain a large voltage holding ratio not only at room temperature but also at temperatures close to the upper limit temperature after long-term use of the element, an antioxidant such as compound (5-1) to compound (5-3) may be further added to the composition. TIFF0007673586000025.tif8688

[0087] A compound with low volatility is effective in maintaining a large voltage holding ratio not only at room temperature but also at temperatures close to the upper limit temperature after the element has been used for a long time. The preferred ratio of the antioxidant is about 50 ppm or more to obtain the effect, and about 600 ppm or less to avoid lowering the upper limit temperature or raising the lower limit temperature. A more preferred ratio is in the range of about 100 ppm to about 300 ppm.

[0088] Preferred examples of the ultraviolet absorber include benzophenone derivatives, benzoate derivatives, triazole derivatives, etc. Light stabilizers such as sterically hindered amines are also preferred. Preferred examples of the light stabilizer include compounds (6-1) to (6-16), etc. The preferred ratio of these absorbers and stabilizers is about 50 ppm or more to obtain the effect, and about 10,000 ppm or less to avoid lowering the maximum temperature or raising the minimum temperature. A more preferred ratio is in the range of about 100 ppm to about 10,000 ppm. TIFF0007673586000026.tif236109

[0089] TIFF0007673586000027.tif240117

[0090] The quencher is a compound that receives the light energy absorbed by the liquid crystal compound and converts it into heat energy, thereby preventing the decomposition of the liquid crystal compound. Preferred examples of the quencher include compounds (7-1) to (7-7). The preferred ratio of these quenchers is about 50 ppm or more to obtain the effect, and about 20,000 ppm or less to lower the minimum temperature. A more preferred ratio is in the range of about 100 ppm to about 10,000 ppm. TIFF0007673586000028.tif15378

[0091] A preferred additive as a stabilizer against ultraviolet light and heat is an amino-tolane compound shown as compound (8) (U.S. Patent No. 6,495,066). TIFF0007673586000029.tif2789 In formula (8), R m and R n is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyloxy having 2 to 12 carbons; X a Yes - NO 2, -CN, -NCS, -F or -OCF 3 And;Y a and Y b is hydrogen or fluorine. A preferred ratio of these stabilizers is in the range of 1 to 20 mass % in order to obtain the desired effect, and more preferably in the range of 5 to 10 mass %.

[0092] A polymerizable compound is added to the composition to make it suitable for a polymer-supported alignment (PSA) type element. Preferred examples of the polymerizable compound are compounds such as acrylate, methacrylate, vinyl compounds, vinyloxy compounds, propenyl ether, epoxy compounds (oxirane, oxetane), and vinyl ketone. More preferred examples are acrylate or methacrylate derivatives. The preferred ratio of the polymerizable compound is about 0.05% by mass or more to obtain the effect, and about 10% by mass or less to prevent viscosity increase and alignment failure. More preferred ratios are in the range of about 0.1% by mass to about 2% by mass. The polymerizable compound is polymerized by irradiation with ultraviolet light. It may be polymerized in the presence of an initiator such as a photopolymerization initiator. Suitable conditions for polymerization, suitable types of initiators, and suitable amounts are known to those skilled in the art and described in the literature. For example, photopolymerization initiators Irgacure 651 (registered trademark; BASF), Irgacure 184 (registered trademark; BASF), or Darocur 1173 (registered trademark; BASF) are suitable for radical polymerization. A preferred ratio of the photopolymerization initiator is in the range of about 0.1% by mass to about 5% by mass, more preferably about 1% by mass to about 3% by mass, based on the mass of the polymerizable compound.

[0093] When storing a polymerizable compound, a polymerization inhibitor may be added to prevent polymerization. The polymerizable compound is usually added to the composition without removing the polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinone, hydroquinone derivatives such as methylhydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, phenothiazine, etc.

[0094] For the purposes of this specification, polar compounds are organic compounds that have polarity and do not include compounds with ionic bonds. Atoms such as oxygen, sulfur, and nitrogen tend to be more electronegative and carry a partial negative charge. Carbon and hydrogen tend to be neutral or carry a partial positive charge. Polarity results from the partial charges not being distributed evenly among different types of atoms in a compound. For example, polar compounds include -OH, -COOH, -SH, -NH 2 , >NH, >N-.

[0095] Seventh, the synthesis method of the component compounds will be explained. These compounds can be synthesized by the methods described in books such as Organic Syntheses (John Wiley & Sons, Inc.), Organic Reactions (John Wiley & Sons, Inc.), Comprehensive Organic Synthesis (Pergamon Press), and New Experimental Chemistry Lectures (Maruzen). The composition is prepared from the compounds thus obtained by a known method. For example, the component compounds are mixed and dissolved in each other by heating.

[0096] Finally, the use of the composition is described. This composition mainly has a lower limit temperature of about -10°C or less, an upper limit temperature of about 70°C or more, and a refractive index anisotropy in the range of about 0.20 to about 0.80. By controlling the ratio of the component compounds or by mixing other liquid crystal compounds, a composition having a refractive index anisotropy in the range of about 0.30 to about 0.60 may be prepared. By trial and error, a composition having a refractive index anisotropy in the range of about 0.40 to about 0.55 may be prepared. This composition can be used as a composition having a nematic phase, or as an optically active composition by adding an optically active compound.

[0097] This composition can be used in elements used for phase control of electromagnetic signals with frequencies from 1 GHz to 10 THz. Application examples include millimeter wave band variable phase shifters, LiDAR (Light Detection and Ranging) elements, and antennas that apply metamaterial technology.

[0098] The dielectric anisotropy of the composition is preferably large in order to reduce the driving voltage of the device. In particular, in a mode in which the electric field applied to the liquid crystal composition is limited by polymer stabilization or encapsulation, the driving voltage tends to be high, so the dielectric anisotropy is preferably as large as possible. The dielectric anisotropy is preferably in the range of 1 to 40, more preferably in the range of 1 to 20. EXAMPLES

[0099] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The present invention also includes a mixture of at least two of the compositions of the examples.

[0100] Measurement method: The characteristics were measured by the following methods. Most of these were methods described in the JEITA standard (JEITA·ED-2521B) established by the Japan Electronics and Information Technology Industries Association (JEITA), or modified methods. No thin film transistors (TFTs) were attached to the TN elements used for the measurements.

[0101] Nematic phase maximum temperature (NI; °C): A sample was placed on the hot plate of a melting point measurement device equipped with a polarizing microscope and heated at a rate of 1 °C / min. The temperature at which a part of the sample changed from a nematic phase to an isotropic liquid was measured. The maximum temperature of the nematic phase is sometimes abbreviated as the "maximum temperature."

[0102] The lowest temperature of the nematic phase (T C;°C): A sample having a nematic phase was placed in a glass bottle and stored in a freezer at 0°C, -10°C, -20°C, -30°C, and -40°C for 10 days, after which the liquid crystal phase was observed. For example, when a sample remained in a nematic phase at -20°C and changed to a crystalline or smectic phase at -30°C, T C The lowest temperature of the nematic phase is sometimes abbreviated as "lower limit temperature."

[0103] Viscosity (bulk viscosity; η; measured at 20°C; mPa·s): An E-type rotational viscometer manufactured by Tokyo Keiki Co., Ltd. was used for the measurement.

[0104] Refractive index anisotropy (when Δn<0.30; measured at 25°C): Measurements were performed using light with a wavelength of 589 nm and an Abbe refractometer with a polarizing plate attached to an eyepiece. After rubbing the surface of the main prism in one direction, a sample was dropped onto the main prism. The refractive index n∥ was measured when the direction of polarized light was parallel to the direction of rubbing. The refractive index n⊥ was measured when the direction of polarized light was perpendicular to the direction of rubbing. The value of refractive index anisotropy was calculated from the formula Δn=n∥-n⊥.

[0105] Refractive index anisotropy (when Δn≧0.30; measured at 25℃): A sample was placed in an element consisting of two glass substrates and aligned in an anti-parallel manner. The retardation in the thickness direction (Rth) of this element was measured using a retardation film / optical material inspection device (manufactured by Otsuka Electronics Co., Ltd., product name: RETS-100), and the refractive index anisotropy (Δn) was calculated from the retardation value (Rth) and the distance between the glass substrates (d: cell gap) using the following formula. The wavelength of the light used was 589 nm. Rth = Δn d

[0106] Dielectric anisotropy (Δε; measured at 25°C): A sample was placed in a TN element with a cell gap of 9μm between two glass substrates and a twist angle of 80°. A sine wave (10V, 1kHz) was applied to this element, and the dielectric constant (ε∥) in the long axis direction of the liquid crystal molecules was measured after 2 seconds. A sine wave (0.5V, 1kHz) was applied to this element, and the dielectric constant (ε⊥) in the short axis direction of the liquid crystal molecules was measured after 2 seconds. The value of the dielectric anisotropy was calculated from the formula Δε=ε∥-ε⊥.

[0107] Refractive index anisotropy at 28 GHz (measured at room temperature): Measured using the method disclosed in Applied Optics, Vol. 44, No. 7, p. 1150 (2005). Refractive index anisotropy was measured by filling a variable short-circuit waveguide with a window material and holding it in a static magnetic field of 0.3 T for 3 minutes. A microwave of 28 GHz was input into the waveguide, and the amplitude ratio of the reflected wave to the incident wave was measured. Measurements were performed by changing the direction of the static magnetic field and the length of the short-circuit tube, and the refractive index (n:ne,no) and loss parameters (α:αe,αo) were determined. Refractive index anisotropy (Δn@28GHz) was calculated from ne-no.

[0108] Tangent delta at 28GHz and dielectric anisotropy (measured at room temperature): The complex dielectric constant (ε', ε") was calculated using the refractive index and loss parameters calculated in the previous section and the following relational equation. Here, c is the speed of light in a vacuum, ω is the angular velocity, and κ is the extinction coefficient. The dielectric anisotropy is expressed by n e From ε'∥, n o From ε' ⊥ The dielectric anisotropy (Δε@28GHz) is calculated as ε'∥-ε' ⊥ Tan δ (tan δ@28GHz) was calculated using the complex dielectric constants (ε', ε") as tan δ=ε" / ε'. Since anisotropy also appears in tan δ, the larger value is shown. ε'=n 2 -κ 2 ε”=2nκ α=2ωκ / c

[0109] The compounds in the examples are represented by symbols based on the definitions in Table 2 below. In Table 2, the configuration of 1,4-cyclohexylene is trans. The number in parentheses after the symbol corresponds to the compound number. The proportion (percentage) of the liquid crystal compound is a mass percentage (mass%) based on the mass of the liquid crystal composition. Finally, the characteristic values ​​of the composition are summarized.

[0110] TIFF0007673586000030.tif245170 TIFF0007673586000031.tif123170

[0111] [Comparative Example 1] Liquid crystal composition 1 2-BTB-O1 (2-3) 7% 3-BTB-O1 (2-3) 7% 4-BTB-O1 (2-3) 7% 4-BTB-O2 (2-3) 7% 5-BTB-O1 (2-3) 6% 1-BB(F)B-2V (2-7) 6% 2-BB(F)B-2V (2-7) 6% 3-BB(F)B-2V (2-7) 7% 3-H2BTB-2 (2-10) 2% 3-H2BTB-3 (2-10) 2% 3-HB(F)TB-2 (2-11) 7% 3-HB(F)TB-3 (2-11) 6% 3-HB(F)TB-4 (2-11) 6% 3-BB(F,F)XB(F,F)-F (3-1) 5% 3-BB(F)B(F,F)-F (3-2) 9% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 10% NI=100.6℃;Tc<-30℃;Δn=0.26;Δε=5.1;η=36.4mPa·s The dielectric anisotropy and tan δ of liquid crystal composition 1 at 28 GHz were as follows. Δε@28GHz=0.62 tan δ@28GHz=0.015

[0112] [Comparative Example 2] Liquid crystal composition 2 2-BTB-O1 (2-3) 8% 3-BTB-O1 (2-3) 8% 4-BTB-O1 (2-3) 8% 4-BTB-O2 (2-3) 8% 5-BTB-O1 (2-3) 7% 3-H2BTB-2 (2-10) 4% 3-H2BTB-3 (2-10) 3% 3-H2BTB-4 (2-10) 2% 3-HB(F)TB-2 (2-11) 9% 3-HB(F)TB-3 (2-11) 8% 3-HB(F)TB-4 (2-11) 8% 3-BB(F,F)XB(F,F)-F (3-1) 1% 3-BB(F)B(F,F)-F (3-2) 14% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 12% NI=99.3℃;Tc<-30℃;Δn=0.26;Δε=5.5;η=36.4mPa·s The dielectric anisotropy and tan δ of liquid crystal composition 2 at 28 GHz were as follows. Δε@28GHz=0.59 tan δ@28GHz=0.014

[0113] [Comparative Example 3] Liquid crystal composition 3 3-HB-O2 (2-1) 8% 1-BB-3 (2-2) 9% 1-BB(F)B-2V (2-7) 4% 2-BB(F)B-2V (2-7) 4% 3-BB(F)B-2V (2-7) 5% 2-BB(F)B-3 (2-7) 10% 2-BB(F)B-5 (2-7) 10% 3-BB(F)B-5 (2-7) 10% 3-BB(2F,5F)B-3 (2-8) 5% 5-HBB(F)B-2 (2-18) 6% 5-HBB(F)B-3 (2-18) 7% 3-BB(F,F)XB(F,F)-F (3-1) 10% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 12% NI=108.9℃;Tc<-20℃;Δn=0.23;Δε=5.2;η=45.8mPa·s The dielectric anisotropy and tan δ of liquid crystal composition 3 at 28 GHz were as follows. Δε@28GHz=0.54 tan δ@28GHz=0.011

[0114] [Comparative Example 4] Liquid crystal composition 4 2-BTB-O1 (2-3) 6% 3-BTB-O1 (2-3) 5% 4-BTB-O1 (2-3) 5% 4-BTB-O2 (2-3) 5% 5-BTB-O1 (2-3) 5% 3-BTTB-O1 (2-4) 13% 5-BTTB-O1 (2-4) 13% 3-BB(F)TB-4 (2-12) 20% 2-BTB(F)TB-5 (2-13) 8% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 10% 3-GB(F)B(F)B(F)-F (3-10) 5% 3-GBB(F)B(F,F)-F (3-11) 2% 4-GBB(F)B(F,F)-F (3-11) 3% NI=130.0℃;Tc<-30℃;Δn=0.37;Δε=4.6 The dielectric anisotropy and tan δ of liquid crystal composition 3 at 28 GHz were as follows. Δε@28GHz=0.85 tan δ@28GHz=0.016

[0115] [Example 1] Liquid crystal composition 5 5-B(F)TB(F)-TC (1-1) 15% 2-BTB-O1 (2-3) 4% 3-BTB-O1 (2-3) 3% 4-BTB-O1 (2-3) 3% 4-BTB-O2 (2-3) 3% 5-BTB-O1 (2-3) 3% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 3-BB(F)TB-4 (2-12) 24% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 5% 3-BB(F)BC (3-20) 10% NI=131.6°C; Δn=0.39; Δε=6.9 The dielectric anisotropy and tan δ of liquid crystal composition 5 at 28 GHz were as follows. Δε@28GHz=0.91 tan δ@28GHz=0.014

[0116] [Example 2] Liquid crystal composition 6 5-B(F)TB(F)-TC (1-1) 15% 2-BTB-O1 (2-3) 5% 3-BTB-O1 (2-3) 5% 4-BTB-O1 (2-3) 5% 4-BTB-O2 (2-3) 4% 5-BTB-O1 (2-3) 4% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 5-BTB(F)TB-2 (2-13) 9% 5-BTB(F)TB-3 (2-13) 9% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 5% 3-GB(F)B(F)B(F)-F (3-10) 5% 3-GBB(F)B(F,F)-F (3-11) 2% 4-GBB(F)B(F,F)-F (3-11) 2% NI=127.2℃;Δn=0.40;Δε=10.5 The dielectric anisotropy and tan δ of liquid crystal composition 6 at 28 GHz were as follows. Δε@28GHz=0.93 tan δ@28GHz=0.014

[0117] [Example 3] Liquid crystal composition 7 5-B(F)TB(F)-TC (1-1) 15% 2-BTB-O1 (2-3) 2% 3-BTB-O1 (2-3) 2% 4-BTB-O1 (2-3) 2% 4-BTB-O2 (2-3) 2% 5-BTB-O1 (2-3) 2% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 3-BB(F)TB-4 (2-12) 24% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 5% 3-GB(F)B(F)B(F)-F (3-10) 5% 3-GBB(F)B(F,F)-F (3-11) 2% 4-GBB(F)B(F,F)-F (3-11) 2% 2O-bt(7F)B(2F)B-3 (2-19) 3% 2O-bt(7F)B(2F)B-4 (2-19) 4% NI= 142.9℃;Δn= 0.40;Δε= 10.9 The dielectric anisotropy and tan δ of liquid crystal composition 7 at 28 GHz were as follows. Δε@28GHz= 0.93 tan δ@28GHz= 0.014

[0118] [Example 4] Liquid crystal composition 8 5-B(F)TB(F)-TC (1-1) 15% 2-BTB-O1 (2-3) 4% 3-BTB-O1 (2-3) 3% 4-BTB-O1 (2-3) 3% 4-BTB-O2 (2-3) 3% 5-BTB-O1 (2-3) 3% 3-BTTB-O1 (2-4) 16% 5-BTTB-O1 (2-4) 16% 5-BTB(F)TB-2 (2-13) 10% 5-BTB(F)TB-3 (2-13) 10% 5-BTB(F)TB-3 (2-13) 5% 3-BB(F,F)XB(F)B(F,F)-F (3-12) 12% NI=127.0℃;Δn=0.41;Δε=10.3 The dielectric anisotropy and tan δ of liquid crystal composition 8 at 28 GHz were as follows. Δε@28GHz=0.97 tan δ@28GHz=0.014

[0119] [Example 5] Liquid crystal composition 9 5-BTB(F,F)-TC (1-1) 15% 5-B(F)TB(Me)-TC (1-1) 10% 5-BB(F)TB-TC (1-2) 5% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 3-BB(F)TB-4 (2-12) 24% 2O-btTB-3 (2-17) 10% 2O-bt(7F)B(2F)B-3 (2-19) 3% 2O-bt(7F)B(2F)B-4 (2-19) 3% NI=143.2℃;Δn=0.44;Δε=11.3 The dielectric anisotropy and tan δ of liquid crystal composition 9 at 28 GHz were as follows. Δε@28GHz=1.00 tan δ@28GHz=0.013

[0120] [Example 6] Liquid crystal composition 10 5-B(F)TB(F)-TC (1-1) 15% 2-BTB-O1 (2-3) 2% 3-BTB-O1 (2-3) 2% 4-BTB-O1 (2-3) 2% 4-BTB-O2 (2-3) 2% 5-BTB-O1 (2-3) 2% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 3-BB(F)BC (3-20) 10% 3-BB(F)TB-4 (2-12) 15% 2O-btTB-3 (2-17) 20% NI=129.7°C; Δn=0.41; Δε=9.9

[0121] [Example 7] Liquid crystal composition 11 5-B(F)TB(F)-TC (1-1) 15% 5-BB(F)TB-TC (1-2) 5% 2-BTB-O1 (2-3) 6% 3-BTB-O1 (2-3) 6% 4-BTB-O1 (2-3) 6% 4-BTB-O2 (2-3) 6% 5-BTB-O1 (2-3) 6% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 5-BTB(F)TB-2 (2-13) 10% 5-BTB(F)TB-3 (2-13) 10% NI = 124.8 °C; Δn = 0.42; Δε = 7.9

[0122] [Example 8] Liquid Crystal Composition 12 5-B(F)TB(F)-TC (1-1) 15% 5-B(Me)TB(F)-TC (1-1) 10% 5-BB(F)TB-TC (1-2) 5% 3-BTTB-O1 (2-4) 25% 5-BTTB-O1 (2-4) 25% 5-BTB(F)TB-2 (2-13) 10% 5-BTB(F)TB-3 (2-13) 10% NI = 144.7 °C; Δn = 0.46; Δε = 11.0

[0123] [Example 9] Liquid Crystal Composition 13 5-B(F)TB(F)-TC (1-1) 10% 5-B(Me)TB(F)-TC (1-1) 10% 5-BB(F)TB-TC (1-2) 5% 2-BTB-O1 (2-3) 2% 3-BTB-O1 (2-3) 2% 4-BTB-O1 (2-3) 2% 4-BTB-O2 (2-3) 2% 5-BTB-O1 (2-3) 2% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 2O-btTB-3 (2-17) 20% 2O-bt(7F)B(2F)B-3 (2-19) 5% 3-BB(F)B-C (3-20) 10% NI = 130.9 °C; Δn = 0.42; Δε = 12.2

[0124] [Example 10] Liquid Crystal Composition 14 5-B(F)TB(F)-TC (1-1) 10% 5-B(Me)TB(F)-TC (1-1) 10% 5-B(F)TB-TC (1-1) 5% 5-BB(F)TB-TC (1-2) 5% 2-BTB-O1 (2-3) 2% 3-BTB-O1 (2-3) 2% 4-BTB-O1 (2-3) 2% 4-BTB-O2 (2-3) 2% 5-BTB-O1 (2-3) 2% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 5-BTB(F)TB-3 (2-13) 10% 2O-btTB-3 (2-17) 20% NI=126.4℃;Δn=0.43;Δε=11.0

[0125] [Example 11] Liquid Crystal Composition 15 5-B(F)TB(F)-TC (1-1) 15% 5-B(Me)TB(F)-TC (1-1) 15% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 5-BTB(F)TB-2 (2-13) 10% 5-BTB(F)TB-3 (2-13) 10% 2O-btTB-3 (2-17) 20% NI=128.3℃;Δn=0.44;Δε=12.3

[0126] [Example 12] Liquid Crystal Composition 16 5-BTB(F,F)-TC (1-1) 15% 5-B(F)TB(Me)-TC (1-1) 10% 5-BB(F)TB-TC (1-2) 5% 3-BTTB-O1 (2-4) 15% 5-BTTB-O1 (2-4) 15% 5-BTB(F)TB-2 (2-13) 9% 5-BTB(F)TB-3 (2-13) 9% 2O-btTB-3 (2-17) 22% NI=133.2℃;Δn=0.46;Δε=11.8

[0127] The Δn of the compositions of Comparative Example 1 to Comparative Example 4 was 0.23 to 0.37, while the Δn of the compositions of Examples 1 to 12 was 0.39 to 0.46. Since each Example has a larger Δn, it is expected that the Δε@28GHz will be larger.

[0128] The compositions of Comparative Example 1 to Comparative Example 4 had Δε@28 GHz in the range of 0.54 to 0.85, and tan δ@28 GHz in the range of 0.011 to 0.016, while the compositions of Example 1 to Example 5 had Δε@28 GHz in the range of 0.91 to 1.00, and tan δ@28 GHz in the range of 0.013 to 0.014.

[0129] Each of the compositions of Examples 1 to 12 contains a compound represented by formula (1). The more such compounds contained in the composition, the larger the dielectric anisotropy at high frequencies becomes. On the other hand, the values ​​of tan δ@28GHz are almost the same. The liquid crystal composition using the compound represented by formula (1) was able to maintain the basic performance of the liquid crystal composition, while relatively increasing Δε@28GHz while maintaining a small value of tan δ@28GHz (by increasing the refractive index anisotropy at 589nm).

[0130] The compositions of Comparative Example 1 to Comparative Example 4 had a Δε of 4.6 to 5.5 at low frequencies (measured at 1 kHz), while the compositions of Examples 1 to 7 had a Δε of 6.9 to 12.3. By using the compound represented by formula (1), it was possible to improve the dielectric anisotropy at low frequencies while maintaining a high phase control property of an electromagnetic wave signal.

[0131] The values ​​of Δn, Δε@28 GHz, and Δε (measured at 1 kHz) of Examples 1 to 7 were larger than those of Comparative Examples 1 to 4, respectively.

[0132] For this reason, the liquid crystal composition using the compound represented by formula (1) can set a large dielectric anisotropy at low frequencies. This has the effect of reducing the driving voltage of the liquid crystal element. In addition, the dielectric anisotropy at high frequencies, which is effective for phase control of electromagnetic signals, can be set large. This allows for more efficient phase control of electromagnetic signals.

[0133] The liquid crystal composition of the present invention has appropriately adjusted properties such as a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, and a relatively low viscosity, and has a large dielectric anisotropy, small tan δ, and a large dielectric anisotropy at low frequencies, particularly in the frequency range where phase control of an electromagnetic wave signal is performed. Therefore, in an element using this liquid crystal composition, the driving voltage is lower and the phase of an electromagnetic wave signal can be controlled with high efficiency. [Industrial Applicability]

[0134] The liquid crystal composition of the present invention satisfies at least one of the characteristics, or has an appropriate balance of at least two of the characteristics, such as a high upper limit temperature of a nematic phase, a low lower limit temperature of a nematic phase, low viscosity, a large refractive index anisotropy in a frequency range where phase control of an electromagnetic wave signal is performed, a large dielectric anisotropy, a small dielectric dissipation factor (tan δ), and a large dielectric anisotropy at a low frequency for reducing a driving voltage. An element containing this composition can be used for phase control of an electromagnetic wave signal with a frequency of 1 GHz to 10 THz.

Claims

1. A liquid crystal composition for use in an element for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz, the liquid crystal composition comprising as a first component at least one compound selected from the group of compounds represented by formula (1), the liquid crystal composition having a refractive index anisotropy of 0.39 to 0.80 at 25°C and a wavelength of 589 nm. In formula (1), R １ is 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, １ Non-adjacent -CH in ２ - may be replaced by -S-, hydrogen may be replaced by fluorine, Ring A １１ is a group selected from the group consisting of group (A) and group (B), In the group (A), non-adjacent —CH ２ - may be replaced by -O- or -S-; in the group (B), at least one -CH= may be replaced by -N=; and in the groups (A) and (B), at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms; Ring A １２ is 1,4-phenylene, in which at least one hydrogen may be replaced by cyano, fluorine, alkyl having 1 to 5 carbons, or cycloalkyl having 3 to 6 carbons; Z １１ is a single bond, -CH=CH-, or -C≡C-, and Z １２ is a single bond, -CH ２ CH ２ -, -CH=CH-, or -C≡C-; Z １２ one of them is -C≡C-; n １ is 1, 2, or 3.

2. 2. The liquid crystal composition according to claim 1, comprising, as a first component, at least one compound selected from the compounds represented by formulas (1-1) to (1-5): In these formulas, R １ is alkyl having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, or alkenyloxy having 2 to 12 carbon atoms, Y １１ , Y １２ and Y １３ is hydrogen, fluorine, methyl, ethyl or cycloalkyl having 3 to 6 carbon atoms; Ring A １２ is 1,4-phenylene, and at least one hydrogen may be replaced by fluorine or alkyl having 1 to 5 carbon atoms.

3. 3. The liquid crystal composition according to claim 1, wherein the ratio of the first component is in the range of 5% by mass to 60% by mass based on the mass of the liquid crystal composition.

4. The liquid crystal composition according to claim 1 , further comprising, as a second component, at least one compound selected from the group of compounds represented by formula (2): In formula (2), R ２１ and R ２２ 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, ２１ and R ２２ Non-adjacent -CH in ２ - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that O atoms are not directly bonded to each other; Ring A ２ is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2,6-benzothiophene, or 7-fluoro-2,6-benzothiophene; Z ２１ and Z ２２ is a single bond, -CH ２ CH ２ -, -CH=CH-, -C≡C-, -COO- or -C≡C-C≡C-; Y ２１ and Y ２２ is hydrogen, fluorine, alkyl having 1 to 5 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms; Y ２３ , Y ２４ and Y ２５ is hydrogen or fluorine, while Y ２４ and Y ２５ is not simultaneously fluorine; n ２ is 0, 1 or 2.

5. 5. The liquid crystal composition according to claim 4, comprising, as a second component, at least one compound selected from the group of compounds represented by formulas (2-1) to (2-21): In these formulas, R ２１ and R ２２ 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, ２１ and R ２２ Non-adjacent -CH in ２ - may be replaced by -O-, -CO-, -COO-, -CH=CH-, or -C≡C-, but O atoms are not directly bonded to each other.

6. The liquid crystal composition according to claim 4 or 5, wherein the ratio of the second component is in the range of 40% by mass to 90% by mass.

7. The liquid crystal composition according to claim 1 , comprising, as a third component, at least one compound selected from the group of compounds represented by formula (3): In formula (3), R ３ 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, ３ Non-adjacent -CH in ２ - may be replaced by -O-, -CO-, -COO-, -CH=CH-, -C≡C- or -S-, provided that O atoms are not directly bonded to each other, and hydrogen may be replaced by fluorine; Ring A ３１ is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; Ring A ３２ is 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, or pyridine-2,5-diyl, pyrimidine-2,5-diyl; Z ３１ and Z ３２ is a single bond, -CH ２ CH ２ -, -CH=CH-, -C≡C-, -COO- or -CF ２ is O-; X ３ is -F, -Cl, -CF ３ , -OCF ３ , -C≡C-CF ３ , -C≡C-OCF ３ , -CN, or -NCS; Y ３１ , Y ３２ and Y ３３ is hydrogen or fluorine, while Y ３１ and Y ３２ is not simultaneously fluorine; n ３ is 1, 2 or 3.

8. 8. The liquid crystal composition according to claim 7, comprising as a third component at least one compound selected from the group of compounds represented by formulas (3-1) to (3-28): In these formulas, R ３ 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, ３ Non-adjacent -CH in ２ - may be replaced by -O-, -CO-, -COO-, -CH=CH-, or -C≡C-, but O atoms are not directly bonded to each other.

9. The liquid crystal composition according to claim 7 or 8, wherein the ratio of the third component is in the range of 5% by mass to 30% by mass.

10. 10. The liquid crystal composition according to claim 1, wherein the dielectric anisotropy at 25° C. at any frequency from 1 GHz to 10 THz is in the range of 0.40 to 2.

0.

11. The liquid crystal composition according to claim 1 , comprising an optically active compound.

12. The liquid crystal composition according to claim 1 , comprising a polymerizable compound.

13. 13. A device used for phase control of an electromagnetic wave signal having a frequency of any one of 1 GHz to 10 THz, comprising the liquid crystal composition according to claim 1.

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