Liquid crystalline compounds, liquid crystalline compositions and applications thereof, elements

Abstract

The present application provides a liquid crystal compound, a liquid crystal composition, and an application and an element thereof. The liquid crystal compound has at least one property of stability to heat, a high clearing point, a low lower limit temperature of a liquid crystal phase, a small viscosity, a very large refractive index anisotropy, and excellent compatibility with other liquid crystal compounds, as a material used in an element for controlling electromagnetic waves in a range of 1 GHz to 10 THz. The liquid crystal composition contains the compound, and the element uses the composition, and electromagnetic wave control can be performed in a wide temperature range. A compound is represented by formula (1). For example, R 1 is an alkyl group having 1 to 12 carbon atoms; L 1 is fluorine; L 2 is hydrogen; L 3 is fluorine; L 4 is methyl; Y 1 is hydrogen; Y 2 is hydrogen; and n is 0.

Description

Technical Field

[0001] This invention relates to a liquid crystal compound, a liquid crystal composition having a nematic phase and positive dielectric anisotropy, and an element comprising the thereof. In particular, it relates to a liquid crystal composition for electromagnetic wave control in the frequency range of 1 GHz to 10 THz and an element comprising the thereof. Background Technology

[0002] Novel applications of liquid crystal compositions, which are mostly used in displays, are attracting attention in high-frequency technologies such as antennas that use liquid crystal compositions to transmit and receive electromagnetic waves.

[0003] Specifically, components used for electromagnetic wave control in the frequency range of 1 GHz to 10 THz include millimeter-wave or microwave band antenna arrays and electromagnetic wave reflectors. Various approaches have been studied for these components, but the use of liquid crystal compositions, which are considered to have fewer malfunctions due to the absence of moving mechanical parts, has attracted attention.

[0004] In communications technology, high-frequency bands have not been fully utilized to date. Due to the demands for ultra-high speed, large capacity, low latency, and multiple simultaneous connections, there is a strong expectation for the effective use of millimeter-wave bands (24GHz–100GHz). Regarding their utilization, frequency band allocation has begun globally. In approximately 20 countries, frequencies in the millimeter-wave band used in communications have been allocated from 24GHz to 29.5GHz. In the United States, this has been expanded to 37GHz–40GHz and 47.2GHz–48.2GHz, and higher frequencies are likely to be allocated in many more countries in the future. In Japan, the 27GHz–29.5GHz band has been allocated to mobile operators for commercial use. As mentioned above, millimeter-wave frequencies, centered around the 28GHz band, are increasingly being utilized in various countries.

[0005] Liquid crystal compositions with dielectric anisotropy exhibit different dielectric constants in the vertical and horizontal directions relative to the orientation direction of the liquid crystal composition at frequencies below the easing frequency (easing frequency) where orientation polarization occurs.

[0006] Even at frequencies higher than the easing frequency, i.e., microwaves to terahertz waves (approximately 10 THz), the value decreases, but a difference in the dielectric constant in the vertical and horizontal directions relative to the orientation direction of the liquid crystal composition is observed, resulting in dielectric constant anisotropy (Non-Patent Document 1). Therefore, the dielectric constant in one direction can be changed by altering the orientation direction of the molecules in the liquid crystal composition according to an external field (electric field).

[0007] By utilizing this property, the orientation of molecules in the liquid crystal composition can change according to an external electric field, thereby changing the dielectric constant. For example, this can enable microwave devices where the transmission characteristics of high-frequency transmission lines can be electrically controlled externally. Regarding such devices, voltage-controlled millimeter-wave band variable phase shifters that fill waveguides with nematic liquid crystal compositions or broadband microwave / millimeter-wave band variable phase shifters that use nematic liquid crystal compositions as dielectric substrates for microstrip lines have been reported (Patent Document 1 and Patent Document 2).

[0008] In addition, research has been conducted in recent years on metamaterials, which exhibit behaviors in electromagnetic waves containing light that are not found in naturally occurring materials. Various electromagnetic wave control elements have been proposed for application in fields such as high-frequency devices, microwave devices, and antennas, based on their properties. As a capacitor control material for transmission lines using metamaterials, liquid crystal compositions whose dielectric constant can be changed by altering the molecular orientation according to an external electric field are also being considered.

[0009] Ideally, such a component for electromagnetic wave control should have high gain and low loss. When considering phase control of high-frequency signals, the required characteristics of the liquid crystal composition are that it has a large dielectric constant anisotropy that enables large phase control in the frequency region used in phase control, and a small dielectric loss tangent (tanδ) that is proportional to the absorbed energy of the electromagnetic wave signal of the liquid crystal composition (Non-Patent Literature 1).

[0010] Liquid crystal compositions are dielectrics, and therefore exhibit polarization (dielectric polarization) relative to an external field (electric field). The dielectric constant is a physical property representing the dielectric's response to an electric field, and its magnitude is related to dielectric polarization. The mechanisms of dielectric polarization can be broadly categorized into three types: electronic polarization, ionic polarization, and orientation polarization. Orientation polarization is polarization associated with the dipole moment, and as mentioned above, it moderates and decreases at frequencies around several hundred kHz to several hundred MHz. Consequently, dielectric polarization at high frequencies (the range from microwaves to terahertz waves (approximately 10 THz)) is only related to electronic and ionic polarization. Furthermore, in lossless dielectrics, the dielectric constant and refractive index exhibit a relationship of ε = n 2 Regarding the relationship between the small ionic polarization of the liquid crystal composition and the large refractive index anisotropy (Δn) under visible light due to electronic polarization, it is assumed that the larger the anisotropy of the dielectric constant (Δε) in the high-frequency region, the larger it is (Non-Patent Document 2). Therefore, a liquid crystal composition with a large refractive index anisotropy is preferred.

[0011] Furthermore, in order to achieve the switching characteristics and high energy efficiency of the element, a low driving voltage is ideal. Therefore, as a liquid crystal composition, it is preferable to have a large dielectric anisotropy even at low frequencies (below the easing frequency).

[0012] In addition, components used for electromagnetic wave control are required to have a wide operating temperature range and short response time. As a characteristic of liquid crystal compositions, they are also required to have a high upper limit temperature of the nematic phase, a low lower limit temperature of the nematic phase, thermal stability, and low viscosity.

[0013] The liquid crystal composition used in the previously described elements is disclosed in Patent Documents 3 and 4.

[0014] [Existing technical documents]

[0015] [Patent Literature]

[0016] [Patent Document 1] International Publication No. 2017 / 201515

[0017] [Patent Document 2] International Publication No. 2017 / 208996

[0018] [Patent Document 3] Japanese Patent Application Publication No. 2004-285085

[0019] [Patent Document 4] Japanese Patent Application Publication No. 2011-74074

[0020] [Non-patent literature]

[0021] [Non-Patent Literature 1] Liquid Crystals (EKISHO), Vol. 23 (No. 1), (2019), pp. 51-55

[0022] [Non-Patent Document 2] "On the Phenomenon of Dielectrics", Electrical Institute of Japan, Ohmsha Corporation, July 25, 1973, pp. 92-95 Summary of the Invention

[0023] [The problem the invention aims to solve]

[0024] Regarding materials used in components for electromagnetic wave control, the 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 also having a large dielectric constant anisotropy (large refractive index anisotropy), a small dielectric loss tangent (tanδ), and a large dielectric constant anisotropy at low frequencies for reducing the driving voltage. Furthermore, it is preferred to have a small viscosity, a large specific resistivity in the driving frequency region, and thermal stability.

[0025] However, the liquid crystal compositions used in previous applications, such as displays, as components for electromagnetic wave control, are not sufficiently robust in terms of characteristics. This is because their characteristics are inadequate for high-frequency control applications, such as those involving high insertion loss and / or insufficient phase shift.

[0026] The development of liquid crystal materials for electromagnetic wave control components is still ongoing. To improve the characteristics of high-frequency control, efforts are being made to develop novel compounds that optimize these components. Furthermore, special liquid crystal compositions are required for use as materials in components used in electromagnetic wave control.

[0027] The object of the present invention is to provide a liquid crystal compound and liquid crystal composition, which are materials used in components for electromagnetic wave control in the frequency range of 1 GHz to 10 THz, and which have the required good properties and excellent property balance, and a component comprising the composition.

[0028] [Technical means to solve the problem]

[0029] The inventors conducted diligent research and discovered that liquid crystal compositions containing liquid crystal compounds represented by formula (1) having a specific structure solve the aforementioned problems, thereby completing the present invention.

[0030] The present invention includes the following items, etc.

[0031] Item 1. A compound represented by formula (1).

[0032]

[0033] In equation (1),

[0034] R 1 It is hydrogen, halogen or alkyl having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen;

[0035] L 1 L 2 L 3 and L 4 It can be hydrogen, fluorine, chlorine, methyl, or ethyl;

[0036] Y 1 and Y 2 It can be hydrogen, fluorine, or chlorine;

[0037] n is 0 or 1.

[0038] Where, when n is 0, L does not exist.1 L 2 L 3 and L 4 The case where any two of them are methyl and the remaining two are hydrogen, fluorine, chlorine or ethyl.

[0039] Item 2. The compound according to Item 1, wherein the compound represented by formula (1) is represented by any one of formulas (1-1) to (1-18).

[0040]

[0041]

[0042] In equations (1-1) to (1-18),

[0043] R 1' It is an alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen;

[0044] L 1' It is fluorine or methyl, L 2' It can be hydrogen, fluorine, or methyl;

[0045] Y 1' It is either hydrogen or fluorine.

[0046] In equations (1-1), (1-2), (1-5), (1-6), and (1-9), L does not exist. 1' and L 2' The case where it is also methyl;

[0047] In equations (1-3), (1-4), (1-7), and (1-8), L does not exist. 1' and L 2' The case where only one of them is methyl.

[0048] Item 3. A liquid crystal composition comprising at least one compound according to Item 1 or Item 2.

[0049] Item 4. The liquid crystal composition according to Item 3 further comprises at least one compound selected from the compounds represented by formula (2) and formula (3).

[0050]

[0051] In equations (2) and (3),

[0052] R 2 and R 3It is a hydrogen, halogen or a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen;

[0053] L 21 L 22 L 23 L 31 L 32 and L 33 It is hydrogen, halogen, alkyl with 1 to 3 carbon atoms, fluorinated alkyl with 1 to 3 carbon atoms, or cycloalkyl with 3 to 5 carbon atoms;

[0054] Y 21 Y 31 Y 32 Y 33 Y 34 Y 35 and Y 36 It is hydrogen or halogen.

[0055] Item 5. The liquid crystal composition according to Item 3 or Item 4, comprising at least one compound selected from the group consisting of compounds represented by formulas (2-1) to (2-10) as the compound represented by formula (2).

[0056]

[0057] In equations (2-1) to (2-10),

[0058] R 2' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-.

[0059] Item 6. The liquid crystal composition according to any one of items 3 to 5, comprising at least one compound selected from the group consisting of compounds represented by formulas (3-1) to (3-11) as the compound represented by formula (3).

[0060]

[0061]

[0062] In equations (3-1) to (3-11),

[0063] R 3' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-;

[0064] Y35' It can be hydrogen, fluorine, or chlorine.

[0065] Item 7. The liquid crystal composition according to any one of Items 3 to 5, wherein, based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) according to Item 1 is in the range of 5% by weight to 25% by weight, and the proportion of the compound represented by formula (2) is in the range of 10% by weight to 55% by weight.

[0066] Item 8. The liquid crystal composition according to any one of Items 3, 4 and 6, wherein, based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) according to Item 1 is in the range of 5% by weight to 25% by weight, and the proportion of the compound represented by formula (3) is in the range of 20% by weight to 50% by weight.

[0067] Item 9. The liquid crystal composition according to any one of Items 3 to 6, wherein, based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) according to Item 1 is in the range of 5% by weight to 25% by weight, the proportion of the compound represented by formula (2) is in the range of 10% by weight to 55% by weight, and the proportion of the compound represented by formula (3) is in the range of 20% by weight to 50% by weight.

[0068] Item 10. The liquid crystal composition according to any one of items 3 to 7, wherein the refractive index anisotropy at 25°C with a wavelength of 589 nm is 0.40 or more.

[0069] Item 11. The liquid crystal composition according to any one of items 3 to 8, wherein the dielectric constant anisotropy at 25°C at a frequency of 1 kHz is 10 or more.

[0070] Item 12. The liquid crystal composition according to any one of items 3 to 9, wherein the dielectric constant anisotropy at 25°C in at least one frequency range from 1 GHz to 10 THz is in the range of 1.0 to 3.0.

[0071] Item 13. The liquid crystal composition according to any one of items 3 to 10, comprising an optically active compound.

[0072] Item 14. The liquid crystal composition according to any one of items 3 to 11, comprising a polymeric compound.

[0073] Item 15. The liquid crystal composition according to any one of items 3 to 12, further comprising at least one of an antioxidant, an ultraviolet absorber, an antistatic agent, and a dichroic pigment.

[0074] Item 16. An element comprising a liquid crystal composition according to any one of items 3 to 13, wherein the element is used for switching such that the switching of dielectric constant can be reversibly controlled by reversibly changing the orientation of liquid crystal molecules.

[0075] Item 17. An element comprising a liquid crystal composition according to any one of items 3 to 13 and for electromagnetic wave control in a frequency range of 1 GHz to 10 THz.

[0076] Item 18. A liquid crystal lens, a birefringent lens for stereoscopic image display, or a light modulation element comprising a liquid crystal composition according to any one of items 3 to 13.

[0077] [The effects of the invention]

[0078] According to the present invention, a liquid crystal compound can be provided that satisfies at least one of the properties of compounds such as thermal stability, high transparency, very large refractive index anisotropy, and excellent compatibility with other liquid crystal compounds. Compositions containing the compounds of the present invention can, while having a high upper limit temperature and a low lower limit temperature of the nematic phase, sufficiently satisfy at least one of the characteristics of compositions such as large dielectric constant anisotropy (large refractive index anisotropy), small dielectric loss tangent (tanδ), and large dielectric constant anisotropy at low frequencies for reducing driving voltage. Furthermore, at least one of the characteristics of compositions such as liquid crystal compositions having low viscosity, large specific resistivity in the driving frequency region, and thermal stability can be sufficiently satisfied. Devices using the compositions exhibit excellent characteristics of electromagnetic wave control over a wide temperature range. Detailed Implementation

[0079] The usage of terms in this specification is as follows. Sometimes, the terms "liquid crystal composition" and "electromagnetic wave control element" are abbreviated as "composition" and "element," respectively. "Electromagnetic wave control element" is a general term for electromagnetic wave control panels and electromagnetic wave control modules. "Liquid crystal compound" is a general term for compounds having a liquid crystal phase such as a nematic or smectic phase, as well as compounds that, although not having a liquid crystal phase, are mixed in the composition for the purpose of adjusting the temperature range, viscosity, dielectric anisotropy, and other properties of the liquid crystal phase. The compound has, for example, 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 for the purpose of forming a polymer in the composition. Liquid crystal compounds having an alkenyl group are not classified as polymerizable compounds in this sense.

[0080] Liquid crystal compositions are prepared by mixing various liquid crystal compounds. The proportion (content) of the liquid crystal compounds is expressed as a weight percentage (wt%) based on the weight of the liquid crystal composition. Additives such as optically active compounds, antioxidants, UV absorbers, UV and heat stabilizers, matting agents, pigments (dichroic pigments), defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, antistatic agents, and magnetic compounds may be added to the liquid crystal composition as needed. Similarly, the proportion (amount) of additives is expressed as a weight percentage (wt%) based on the weight of the liquid crystal composition, similar to the proportion of liquid crystal compounds. Sometimes parts per million (ppm) are also used. The proportions of polymerization initiators and polymerization inhibitors are exceptionally expressed based on the weight of the polymerizable compounds.

[0081] Sometimes the "upper limit temperature of the nematic phase" is simply referred to as the "upper limit temperature". Sometimes the "lower limit temperature of the nematic phase" is simply referred to as the "lower limit temperature". The expression "increasing the dielectric anisotropy" means that the value of the dielectric constant increases positively when the dielectric constant anisotropy is positive, and it means that the value increases negatively when the dielectric constant anisotropy is negative.

[0082] Sometimes, at least one compound selected from the group of compounds represented by formula (1) is simply referred to as "compound (1)". "Compound (1)" means one or more compounds represented by formula (1). The same applies to compounds represented by other formulas. "At least one" in relation to "substitutable" means that not only the position but also the number of such compounds can be chosen without limitation.

[0083]

[0084] The following explanation uses compound (1z) as an example. In formula (1z), the notations for α and β enclosed by hexagons correspond to ring α and ring β, respectively, representing six-membered rings, fused rings, and the like. When the subscript 'x' is 2, there are two rings α. The two groups represented by the two rings α can be the same or different. This rule applies to multiple rings α when the subscript 'x' is greater than 2. This rule also applies to other notations such as bonding group Z. A diagonal line cut across one side of ring β indicates that any hydrogen on ring β can be substituted by a substituent (-Sp-P). The subscript 'y' indicates the number of substituents substituted. When the subscript 'y' is 0, this substitution does not exist. When the subscript 'y' is 2 or greater, multiple substituents (-Sp-P) exist on ring β. In this case, the rule of "can be the same or different" also applies. Furthermore, this rule also applies when the notation Ra is used for multiple compounds.

[0085] In formula (1z), for example, a statement such as "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. Here, the group represented by Ra may be the same as or different from the group represented by Rb. The rule also applies when the notation Ra is used for multiple compounds. The rule also applies when multiple Ra are used for a single compound.

[0086] Sometimes, at least one compound selected from the compounds represented by formula (1z) is simply referred to as "compound (1z)". "Compound (1z)" means one compound, a mixture of two compounds, or a mixture of three or more compounds represented by formula (1z). The same applies to compounds represented by other formulas. The statement "at least one compound selected from the compounds represented by formula (1z) and formula (2z)" means at least one compound selected from the group consisting of compounds (1z) and compounds (2z).

[0087] The statement "at least one 'A'" means that the number of 'A's is arbitrary. Regarding the statement "at least one 'A' can be substituted by 'B'", when there is only one 'A', the position of 'A' is arbitrary; when there are two or more 'A's, their positions can also be chosen without restriction. Sometimes the statement "at least one -CH2- can be substituted by -O-" is used. In this case, -CH2-CH2-CH2- can be converted to -O-CH2-O- by substituting a non-adjacent -CH2- with -O-. However, there is no case of adjacent -CH2- being substituted with -O-. This is because the substitution would generate -OO-CH2- (peroxide).

[0088] In liquid crystal compounds, alkyl groups, when simply referred to as "alkyl," are either straight-chain or branched-chain alkyl groups, excluding cycloalkyl groups unless otherwise specified. For example, alkyl groups having 1 to 12 carbon atoms refer to straight-chain or branched-chain alkyl groups having 1 to 12 carbon atoms. Straight-chain alkyl groups are preferred over branched-chain alkyl groups. The same applies to terminal groups such as alkoxy and alkenyl groups. For stereoconfigurations related to 1,4-cyclohexylene, the trans configuration is preferred over the cis configuration to increase the upper temperature limit. 2-Fluoro-1,4-phenylene refers to the following two divalent groups. In the chemical formula, fluorine can be to the left (L) or to the right (R). The above rules also apply to divalent groups of asymmetric rings such as 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridin-2,5-diyl, pyrimidin-2,5-diyl, 1,3-dioxane-2,5-diyl, and tetrahydropyran-2,5-diyl. Furthermore, to increase the upper limit temperature, the preferred tetrahydropyran-2,5-dimethyl group is right-facing (R).

[0089]

[0090] Similarly, bonding groups such as carbonyl groups can be either -COO- or -OCO-.

[0091] In the chemical formula of the constituent compound, the terminal group R 1 The notation is used for a variety of compounds. In these compounds, any two Rs 1 The groups represented can be the same or different. For example, there is R in compound (1-1). 1' The methyl group is R in compounds (1-2). 1' In the case of an ethyl group, R also exists for compound (1-1). 1' The ethyl group is R in compounds (1-2). 1' For the case of propyl. The rule also applies to R. 2 R 3 R 4 R 5 R 6 R 71 R 72 The symbol for "etc".

[0092] The present invention also includes the following: (a) the composition further comprising at least one additive selected from optically active compounds, antioxidants, ultraviolet absorbers, stabilizers for ultraviolet light and heat, matting agents, pigments (dichroic pigments), defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, antistatic agents, magnetic compounds, etc. (b) an element comprising the composition. (c) an element comprising the composition and used for controlling electromagnetic wave signals at any frequency from 1 GHz to 10 THz. (d) the composition further comprising a polymerizable compound and an element comprising the composition. (e) use of the composition as a composition having a nematic phase. (f) use as an optically active composition by adding an optically active compound to the composition.

[0093] The liquid crystal composition of the present invention exhibits large dielectric constant anisotropy and small dielectric loss tangent (tanδ) in the frequency region of electromagnetic wave signals in the range of 1 GHz to 10 THz. Therefore, it is suitable not only for use as a component associated with electromagnetic waves (microwaves) in the range of 1 GHz to 10 THz, but also suitable for use with electromagnetic waves (microwaves) in the range of 1 GHz to 50 GHz.

[0094] 1. Compound (1)

[0095] The compound (1) of the present invention will be described in the following order. A preferred form of compound (1) will be described in section 1-1. A preferred form of compound (1) will be shown in section 1-2. A method for synthesizing compound (1) will be described in section 1-3.

[0096] 1-1. Morphology of compound (1)

[0097] The compound (1) of the present invention will be described. Preferred examples of terminal groups, bonding groups, etc. in compound (1) and the effects of these groups on physical properties also apply to the lower form of compound (1).

[0098]

[0099] In equation (1), R 1 It is hydrogen, halogen or alkyl having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen.

[0100] The preferred stereoconfiguration of the -CH=CH- group in the alkenyl group depends on the position of the double bond. Among alkenyl groups such as -CH=CHCH3, -CH=CHC2H5, -CH=CHC3H7, -CH=CHC4H9, -C2H4CH=CHCH3, or -C2H4CH=CHC2H5, the trans configuration is preferred. Among alkenyl groups such as -CH2CH=CHCH3, -CH2CH=CHC2H5, or -CH2CH=CHC3H7, the cis configuration is preferred. Alkenyl compounds with preferred stereoconfigurations exhibit high transparency points or a wide temperature range for liquid crystal phases. Detailed explanations can be found in "Molecular Crystals and Liquid Crystals (Mol.Cryst.Liq.Cryst.)," 1985, 131, 109 and "Molecular Crystals and Liquid Crystals (Mol.Cryst.Liq.Cryst.)," 1985, 131, 327.

[0101] R 1 Preferred examples are alkyl, alkoxy, alkoxyalkyl, alkenyl, alkynyl, and alkenyloxy. R 1 Further preferred examples are alkyl, alkoxy, alkenyl and alkynyl groups.

[0102] Examples of alkyl groups are -CH3, -C2H5, -C3H7, -C4H9, and -C5H. 11 -C6H 13 -C7H 15 -C8H 17 -C9H 19 -C 10 H 21-C 11 H 23 and -C 12 H 25 .

[0103] Examples of alkoxy groups are -OCH3, -OC2H5, -OC3H7, -OC4H9, and -OC5H. 11 -OC6H 13 -OC7H 15 -OC8H 17 -OC9H 19 -OC 10 H 21 and -OC 11 H 23 .

[0104] Examples of alkoxyalkyl groups are -CH2OCH3, -CH2OC2H5, -CH2OC3H7, -(CH2)2-OCH3, -(CH2)2-OC2H5, -(CH2)2-OC3H7, -(CH2)3-OCH3, -(CH2)4-OCH3 and -(CH2)5-OCH3.

[0105] Examples of alkenyl groups are -CH=CH2, -CH=CHCH3, -CH2CH=CH2, -CH=CHC2H5, -CH2CH=CHCH3, -(CH2)2-CH=CH2, -CH=CHC3H7, -CH2CH=CHC2H5, -(CH2)2-CH=CHCH3 and -(CH2)3-CH=CH2.

[0106] Examples of alkynyl groups are -C≡CH, -C≡CCH3, -C≡CC2H5, -C≡CC3H7, -C≡CC4H9, and -C≡CC5H. 11 and -C≡CC6H 13 .

[0107] Examples of alkenyloxy groups are -OCH2CH=CH2, -OCH2CH=CHCH3 and -OCH2CH=CHC2H5.

[0108] Examples of alkyl groups with at least one hydrogen atom substituted by a halogen include -CH2F, -CHF2, -CF3, -(CH2)2-F, -CF2CH3, -CF2CH2F, -CF2CHF2, -CH2CF3, -CF2CF3, -(CH2)3-F, -CF2CH2CH3, -CH2CHFCH3, -CH2CF2CH3, -(CF2)3-F, -CF2CHFCF3, -CHFCF2CF3, -(CH2)4-F, -CF2(CH2)2CH3, -(CF2)4-F, -(CH2)5-F, -(CF2 )5-F, -CH2Cl, -CHCl2, -CCl3, -(CH2)2-Cl, -CCl2CH3, -CCl2CH2Cl, -CCl2CHCl2, -CH2CCl3, -CCl2CCl3, -(CH2)3-Cl, -CCl2CH2 CH3, -(CCl2)3-Cl, -CCl2CHClCCl3, -CHClCCl2CCl3, -(CH2)4-Cl, -(CCl2)4-Cl, -CCl2(CH2)2CH3, -(CH2)5-Cl and -(CCl2)5-Cl.

[0109] Examples of alkoxy groups with at least one hydrogen atom substituted by a halogen include -OCH2F, -OCHF2, -OCF3, -O-(CH2)2-F, -OCF2CH2F, -OCF2CHF2, -OCH2CF3, -O-(CH2)3-F, -O-(CF2)3-F, -OCF2CHFCF3, -OCHFCF2CF3, -O(CH2)4-F, -O-(CF2)4-F, -O-(CH2)5-F, -O-(CF2)5-F, and -OCH2CHFCH. 2CH3, -OCH2Cl, -OCHCl2, -OCCl3, -O-(CH2)2-Cl, -OCCl2CH2Cl, -OCCl2CHCl2, -OCH2CCl3, -O-(CH2)3-Cl, -O-( CCl2)3-Cl, -OCCl2CHClCCl3, -OCHClCCl2CCl3, -O(CH2)4-Cl, -O-(CCl2)4-Cl, -O-(CH2)5-Cl and -O-(CCl2)5-Cl.

[0110] Examples of alkenyl groups with at least one hydrogen atom substituted by a halogen are -CH=CHF, -CH=CF2, -CF=CHF, -CH=CHCH2F, -CH=CHCF3, -(CH2)2-CH=CF2, -CH2CH=CHCF3, -CH=CHCF2CF3, -CH=CHCl, -CH=CCl2, -CCl=CHCl, -CH=CHCH2Cl, -CH=CHCCl3, -(CH2)2-CH=CCl2, -CH2CH=CHCCl3 and -CH=CHCCl2CCl3.

[0111] In equation (1), L 1 L 2 L 3 and L 4 It can be hydrogen, fluorine, chlorine, methyl, or ethyl. L 1 Preferred examples are fluorine or methyl, L 2 Preferred examples are hydrogen, fluorine, or methyl, L 3 Preferred examples are hydrogen, fluorine, methyl or ethyl, L 4 Preferred examples are hydrogen or methyl.

[0112] In equation (1), Y 1 and Y 2 It can be hydrogen, fluorine, or ethyl. Y 1 Preferred examples are hydrogen or fluorine, Y 2 Preferred examples are hydrogen or fluorine.

[0113] In equation (1), L 1 L 2 L 3 L 4 Y 1 and Y 2 In order to lower the lower limit temperature, it is preferable that at least two are not hydrogen atoms. Additionally, L... 1 L 2 L 3 L 4 Y 1 and Y 2 In this process, at least one component is preferably fluorine.

[0114] In equation (1), n ​​is 0 or 1.

[0115] Where, when n is 0, L does not exist. 1 L 2 L 3 and L 4 The case where any two of the elements are methyl and the remaining two are hydrogen, fluorine, chlorine, or ethyl. That is, when n is 0, there is no L. 1 L 2 L 3 and L4 Only the case where any two are methyl groups. Specifically, there is no L. 1 With L 3 L 1 With L 4 or L 3 With L 4 The case where it is also a methyl group. Additionally, when n is 0 and L... 4 When it is methyl, L is not present. 1 L 2 L 3 Y 1 and Y 2 The case where it is both hydrogen.

[0116] As described above, by appropriately selecting the types of terminal groups, bonding groups, etc., compounds with the target properties can be obtained. Since the physical properties of the compounds do not differ significantly, compound (1) can contain a greater amount of [unspecified substance] than naturally occurring compounds. 2 H (deuterium) 13 C isotopes.

[0117] 1-2. Preferred state of compound (1)

[0118] The preferred states of compound (1) are compounds (1-1) to compounds (1-18).

[0119]

[0120]

[0121]

[0122] In equations (1-1) to (1-18),

[0123] R 1' It is an alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen;

[0124] L 1' It is fluorine or methyl, L 2' It can be hydrogen, fluorine, or methyl;

[0125] Y 1' It is either hydrogen or fluorine.

[0126] 1-3. Synthesis of compound (1)

[0127] The synthesis of compound (1) will be described. Compound (1) can be synthesized by appropriately combining methods of organic synthetic chemistry. Methods for introducing target terminal groups, rings, and bonding groups into the starting material are described in books such as *Organic Syntheses* (John Wiley & Sons, Inc.), *Organic Reactions* (John Wiley & Sons, Inc.), *Comprehensive Organic Synthesis* (Pergamon Press), and *New Lectures on Experimental Chemistry* (Maruzen). An example of the synthesis of compound (1) is described in Example 1.

[0128] 2. Composition

[0129] The composition of the present invention will be described in the following order: First, the structure of the component compounds in the composition will be described. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition will be described. Third, the combination of the components in the composition, the preferred proportions of the components, and the basis thereof will be described. Fourth, the preferred form of the added component compounds will be described. Fifth, the form of the added preferred component compounds will be shown. Sixth, additives that can be added to the composition will be described. Finally, the use of the composition will be described.

[0130] First, the structures of the constituent compounds in the composition will be described. The compositions of the present invention are classified as Composition A and Composition B. Composition A may contain liquid crystal compounds selected from compounds (1), (2), and (3), as well as other liquid crystal compounds, additives, etc. "Other liquid crystal compounds" are liquid crystal compounds that are different from compounds (1), (2), and (3). Such compounds are mixed in the composition for the purpose of further adjusting the properties. In order to prepare a liquid crystal composition having the desired refractive index anisotropy or dielectric constant anisotropy at high frequencies, the "other liquid crystal compounds" are preferably liquid crystal compounds with low refractive index anisotropy, such as those that do not use monocyclic compounds or do not contain binding groups, like bicyclic compounds. Additives include optically active compounds, antioxidants, ultraviolet absorbers, stabilizers for ultraviolet light and heat, matting agents, pigments (dichromatic pigments), defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, antistatic agents, polar compounds, etc.

[0131] Composition B substantially contains only liquid crystal compounds selected from compounds (1), (2), and (3). "Substantially" means that the composition may contain additives but not other liquid crystal compounds. Composition B has fewer components than composition A. From the viewpoint of cost reduction, composition B is superior to composition A. From the viewpoint that properties can be further adjusted by mixing with other liquid crystal compounds, composition A is superior to composition B.

[0132] Second, the main characteristics of the component compounds and the main effects of these compounds on the properties of the composition are described. Based on the effects of this invention, the main characteristics of the component compounds are summarized in Table 1. In Table 1, L indicates large or high, M indicates moderate, and S indicates small or low. The symbols L, M, and S are classifications based on qualitative comparisons between the component compounds, and 0 (zero) indicates a value approximately zero or close to zero.

[0133] Table 1 Properties of the compounds

[0134] compound (1) (2) (3) Upper limit temperature L S M to L Viscosity L S M to L Refractive index anisotropy L M L Dielectric constant anisotropy M to L M M

[0135] When component compounds are mixed into a composition, the main effects of the component compounds on the properties of the composition are as follows.

[0136] Compound (1) primarily enhances the anisotropy of the refractive index and dielectric constant of the liquid crystal composition, and also increases the upper limit temperature. The upper and lower limits of the temperature can be controlled to some extent by controlling the number of substituents on the benzene ring of compound (1). Specifically, decreasing the number of substituents tends to increase both the upper and lower limits. Increasing the number of substituents tends to decrease both the upper and lower limits.

[0137] Compound (2) primarily improves the refractive index anisotropy of the liquid crystal composition, improves the dielectric constant anisotropy, and reduces viscosity. Similar to compound (1), from the viewpoint of lowering the lower limit temperature of the liquid crystal composition, the number of substituents is preferably 1 or 2. From the viewpoint of reducing viscosity, the number of substituents is preferably 1.

[0138] Compound (3) mainly has the effects of improving the anisotropy of the refractive index of the liquid crystal composition, improving the anisotropy of the dielectric constant, and increasing the upper limit temperature. The relationship between the number of substituents on the benzene ring and the upper and lower limit temperatures is the same as that of compound (1). From the viewpoint of lowering the lower limit temperature of the liquid crystal composition, the number of substituents is preferably 2 or 3.

[0139] Third, the combination of components in the composition, the preferred proportions of the component compounds, and the basis thereof are explained. From the viewpoint of expanding the temperature range of the nematic phase, improving the anisotropy of the refractive index and the anisotropy of the dielectric constant, and reducing the viscosity, the preferred combination of components in the composition is compound (1) + compound (2) + compound (3).

[0140] Based on the weight of the liquid crystal composition, in order to expand the temperature range of the nematic phase while improving refractive index anisotropy and increasing Δε in the high-frequency region, the preferred proportion of compound (1) is in the range of about 5% to about 25% by weight. More preferably, the proportion is in the range of about 5% to about 20% by weight. Particularly preferred is the proportion in the range of about 5% to about 15% by weight.

[0141] Based on the weight of the liquid crystal composition, in order to improve refractive index anisotropy and increase Δε in the high-frequency region while expanding the temperature range of the nematic phase and reducing viscosity, the preferred proportion of compound (2) is in the range of about 10 wt% to about 55 wt%. More preferably, the proportion is in the range of about 20 wt% to about 50 wt%. Particularly preferred is the proportion in the range of about 20 wt% to about 45 wt%.

[0142] Based on the weight of the liquid crystal composition, in order to expand the temperature range of the nematic phase while improving refractive index anisotropy and increasing Δε in the high-frequency region, the preferred proportion of compound (3) is in the range of about 20% to about 50% by weight. More preferably, the proportion is in the range of about 25% to about 40% by weight. Particularly preferred is the proportion in the range of about 25% to about 35% by weight.

[0143] Fourth, the preferred form of the added component compounds is described.

[0144] In compounds (2) and (3), R 2 and R 3 It is a hydrogen, halogen, or straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, and at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, wherein at least one hydrogen may be substituted with a halogen.

[0145] In compounds (2) and (3), R is preferred to improve stability against ultraviolet light or heat. 2 Or R 3 The preferred compounds are methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, or ethoxy. To reduce viscosity, methyl, ethyl, propyl, butyl, pentyl, methoxy, or ethoxy are preferred.

[0146] In compounds (2-1) to (2-10) and compounds (3-1) to (3-11), R 2' and R 3' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-.

[0147] In compounds (2) and (3), L 21 L 22 L 23 L 31 L 32 and L 33 It is hydrogen, halogen, alkyl group having 1 to 3 carbon atoms, fluorinated alkyl group having 1 to 3 carbon atoms, or cycloalkyl group having 3 to 5 carbon atoms. To increase the upper temperature limit, L is preferred. 21 L 22 L 23 L 31 L 32 and L 33 For hydrogen, in order to improve the anisotropy of the dielectric constant, L is preferred. 21 L 22 L 23 L 31 L 32 and L 33 The fluorine or chlorine is preferred, and to lower the lower limit temperature, L is preferred. 21 L 22 L 23 L 31 L 32 and L 33 It can be fluorine, chlorine, methyl, or ethyl.

[0148] In compounds (2) and (3), Y 21 Y 31 Y 32 Y 33 Y 34 Y 35 and Y 36 It is either hydrogen or halogen. To improve refractive index anisotropy, Y is preferred. 21 Y 31 Y 32 Y 33 Y 34 Y 35 and Y 36 For hydrogen, in order to improve dielectric anisotropy and to lower the lower limit temperature, Y is preferred. 21 Y 31 Y 32 Y 33 Y 34 Y 35and Y 36 It is either fluorine or chlorine.

[0149] In compounds (3-1) to (3-11), Y 35' It can be hydrogen, fluorine, or chlorine.

[0150] In compound (2), L 21 L 22 and L 23 In order to lower the lower limit temperature, at least one of the components is preferably methyl.

[0151] In compound (3), L 31 L 32 and L 33 In order to lower the lower limit temperature, at least one of the components is preferably methyl.

[0152] In compounds (1), (2), and (3), L is preferred in order to increase the overall dielectric constant anisotropy of the liquid crystal composition. 2 and Y 1 L 4 and Y 2 L 21 and L 22 L 23 and Y 21 Y 33 and Y 35 L 31 and L 32 or L 33 and Y 36 It is not simultaneously a halogen.

[0153] Fifth, the state of the added preferred component compound is shown.

[0154] The preferred compound (2) is compound (2-1) to compound (2-10).

[0155]

[0156] In equations (2-1) to (2-10),

[0157] R 2' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-.

[0158] More preferably, at least one of the compounds (2) is compound (2-2), compound (2-5), or compound (2-6).

[0159] The preferred compound (3) is compound (3-1) to compound (3-11).

[0160]

[0161] In equations (3-1) to (3-11),

[0162] R 3' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-; Y 35' It can be hydrogen, fluorine, or chlorine.

[0163] More preferably, at least one of the compounds (3) is compound (3-3), compound (3-5), compound (3-8), compound (3-9) or compound (3-10).

[0164] Sixth, additives that may be added to the composition are described. These additives include optically active compounds, antioxidants, ultraviolet absorbers, stabilizers for ultraviolet light and heat, matting agents, pigments (dichroic pigments), defoamers, polymerizable compounds, polymerization initiators, polymerization inhibitors, antistatic agents, polar compounds, etc. Unless otherwise specified, the mixing ratios of these additives are based on the weight of the liquid crystal composition.

[0165] The combination of additives used is arbitrary; for example, different types of antioxidants can be combined. For instance, different types of additives can be combined, such as by combining antioxidants with UV absorbers and stabilizers.

[0166] Optically active compounds are added to the composition for the purpose of inducing a helical structure in the liquid crystal to impart a twist angle. Examples of such compounds are compounds (8-1) to compounds (8-5). The preferred proportion of the optically active compound is about 5% by weight or less. More preferably, the proportion is in the range of about 0.01% by weight to about 2% by weight.

[0167]

[0168] Antioxidants are added to the composition to prevent a decrease in resistivity caused by heating in the atmosphere or to maintain a high voltage retention rate not only at room temperature but also at temperatures close to the upper limit after prolonged use of the component. Preferred examples of antioxidants are compounds (9) in which t is an integer from 1 to 9.

[0169]

[0170] In compound (9), the preferred t is 1, 3, 5, 7, or 9. More preferably, t is 7. Compound (9) with a t of 7 is effective for maintaining a large voltage retention rate not only at room temperature but also at temperatures close to the upper limit temperature after prolonged use of the component, due to its low volatility. To achieve this effect, the preferred proportion of the antioxidant is about 50 ppm or more, and the preferred proportion of the antioxidant is about 600 ppm or less to avoid lowering the upper limit temperature or raising the lower limit temperature. More preferably, the proportion is in the range of about 100 ppm to about 300 ppm.

[0171] Preferred examples of ultraviolet absorbers include benzophenone derivatives, benzoic acid ester derivatives, triazole derivatives, etc. Additionally, light stabilizers such as sterically hindered amines are also preferred. Preferred examples of light stabilizers are compounds (10⁻¹) to (10⁻¹⁶), etc. To obtain the aforementioned effect, the preferred proportion of these absorbers or stabilizers is about 50 ppm or more, and to avoid lowering the upper limit temperature or raising the lower limit temperature, the preferred proportion of these absorbers or stabilizers is about 10,000 ppm or less. More preferably, the proportion is in the range of about 100 ppm to about 10,000 ppm.

[0172]

[0173]

[0174] Preferred additives as stabilizers against ultraviolet light and heat include amino-trans compounds as shown in compound (11) (US Patent No. 6,495,066).

[0175]

[0176] In equation (11), R m and R n It 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; X a For -NO2, -C≡N, -N=C=S, fluorine, or -OCF3; Y a and Y b The stabilizer is either hydrogen or fluorine. To achieve the desired effect, the preferred proportion of these stabilizers is in the range of 1% to 20% by weight, and more preferably in the range of 5% to 10% by weight.

[0177] Matting agents are compounds that prevent the decomposition of liquid crystal compounds by accepting light energy absorbed by the liquid crystal compound and converting it into heat energy. To achieve the desired effect, the preferred proportion of these matting agents is about 50 ppm or more, and to lower the lower limit temperature, the preferred proportion is about 20,000 ppm or less. More preferably, the proportion is in the range of about 100 ppm to about 10,000 ppm.

[0178] To suit components in a guest-host (GH) mode, dichroic dyes such as azo dyes and anthraquinone dyes are added to the composition. The preferred proportion of the dye is in the range of about 0.01% by weight to about 10% by weight. To prevent foaming, defoamers such as dimethyl silicone oil and methylphenyl silicone oil are added to the composition. To achieve the desired effect, the preferred proportion of the defoamer is about 1 ppm or more; to prevent poor display, the preferred proportion of the defoamer is about 1000 ppm or less. More preferably, the proportion is in the range of about 1 ppm to about 500 ppm.

[0179] To suit the polymer-stabilized components, a polymerizable compound is added to the composition. Preferred examples of polymerizable compounds are acrylates, methacrylates, vinyl compounds, ethylene oxide compounds, propylene ethers, epoxy compounds (oxetane, oxetane), vinyl ketones, and other compounds having groups capable of polymerization. Further preferred examples are acrylates or derivatives of methacrylates. To achieve the desired effect, the preferred proportion of the polymerizable compound is about 0.05% by weight or more, and to prevent an increase in the driving temperature, the preferred proportion of the polymerizable compound is about 20% by weight or less. A further preferred proportion is in the range of about 0.1% by weight to about 10% by weight. The polymerizable compound is polymerized by ultraviolet irradiation. Polymerization can also be carried out in the presence of a polymerization initiator such as a photopolymerization initiator. Suitable conditions for polymerization, suitable types and amounts of initiators are known to those skilled in the art and are described in the literature. For example, Irgacure 651 (registered trademark; BASF), Irgacure 184 (registered trademark; BASF) or Darocur 1173 (registered trademark; BASF) are suitable photopolymerization initiators for free radical polymerization. Based on 100 parts by weight of the polymerizable compound, the preferred proportion of the photopolymerization initiator is from about 0.1 parts by weight to about 5 parts by weight. More preferably, the proportion is from about 1 part by weight to about 3 parts by weight.

[0180] To prevent polymerization, polymerization inhibitors may be added when storing polymerizable compounds. Polymerizable compounds are typically added to the composition with the polymerization inhibitors still attached. Examples of polymerization inhibitors include hydroquinone, hydroquinone derivatives such as methyl hydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, and phenothiazines.

[0181] In this specification, polar compounds are polar organic compounds and do not include compounds with ionic bonds. Atoms such as oxygen, sulfur, and nitrogen are electronegative and tend to have a partial negative charge. Carbon and hydrogen are neutral or tend to have a partial positive charge. Polarity arises from the uneven distribution of partial charge among different types of atoms in the compound. For example, polar compounds have at least one partial structure such as -OH, -COOH, -SH, -NH2, >NH, >N-.

[0182] Finally, the uses of the composition will be described. Because the composition of the present invention has a lower limit temperature of about -10°C or less and an upper limit temperature of about 70°C or more, it can be used not only as a composition having a nematic phase, but also as an optically active composition by adding an optically active compound.

[0183] The dielectric constants of an oriented liquid crystal composition differ in the vertical and horizontal directions. Therefore, it exhibits dielectric anisotropy as a characteristic.

[0184] Not limited to antenna elements, elements using liquid crystal compositions typically comprise two substrates sandwiching the liquid crystal composition in layers. Liquid crystal molecules align (orient) in one direction via an alignment film located at their interface. In the absence of an external field, the liquid crystal molecules within the element are aligned in one direction due to the alignment-restricting force of the alignment film. If an external field is applied, the liquid crystal molecules within the element deviate from their alignment in the alignment film and align towards the direction of the external field. Furthermore, if the external field is removed again, the liquid crystal molecules return to their original unidirectional alignment due to the alignment-restricting force of the alignment film. Thus, the orientation of the liquid crystal molecules within the element can be controlled according to the direction or magnitude of the external field, thereby controlling the tilt (angle) of the liquid crystal molecules within the element relative to one direction. Since the liquid crystal composition exhibits dielectric anisotropy, by controlling the angle of the liquid crystal molecules within the element relative to one direction, the dielectric constant of the liquid crystal composition layer within the element relative to that direction can be controlled. For example, the dielectric constant of a liquid crystal composition layer in an element in one direction when there is no external field is the dielectric constant of the liquid crystal composition in the vertical direction. By applying an external field perpendicular to one direction, it can be changed to the dielectric constant of the liquid crystal composition in the horizontal direction.

[0185] As described above, the liquid crystal composition of the present invention can be used as a switching element in which the dielectric constant can be reversibly controlled by reversibly changing the orientation of liquid crystal molecules.

[0186] The angle of the liquid crystal molecules within the element can be controlled using an electric field as the external field. The voltage required to drive the liquid crystal molecules is the driving voltage. To control the angle of the liquid crystal molecules, the dielectric anisotropy of the liquid crystal composition at 25°C within a frequency range of less than 1 MHz is required to be at least greater than 2. To further reduce the driving voltage, it is necessary to further increase the dielectric anisotropy at 25°C within a frequency range of less than 1 MHz, preferably 5 or more, and more preferably 10 or more.

[0187] As described above, the greater the refractive index anisotropy (Δn) in the visible light region (e.g., wavelength 589 nm), the greater the dielectric constant anisotropy (Δε) in the high-frequency region (the range from microwaves to terahertz waves (approximately 10 THz)). Liquid crystal compositions containing the compound represented by formula (1) of this application preferably have a refractive index anisotropy (Δn) of 0.30 or more at 25°C. Particularly in applications involving high frequencies, Δn is more preferably 0.40 or more, and particularly preferably 0.45 or more.

[0188] To achieve phase difference control in the high-frequency region, the dielectric constant anisotropy in the high-frequency region is preferably 0.5 or higher. For more suitable phase control, it is necessary to increase the dielectric constant anisotropy in the high-frequency region. For sufficient phase control, the dielectric constant anisotropy is preferably 1.0 or higher, more preferably 1.2 or higher.

[0189] Furthermore, the composition of the present invention can be used in components for electromagnetic wave control in the frequency range of 1 GHz to 10 THz. Examples of applications include, in addition to antenna arrays or electromagnetic wave reflectors, millimeter-wave bandgap phase shifters, millimeter-wave radar, etc. Various applications and methods have been developed using components based on the composition of the present invention. As antenna arrays, antenna arrays utilizing metamaterial technology are being developed; furthermore, as electromagnetic wave reflectors, intelligent reflecting surfaces (IRS), reconfigurable intelligent surfaces (RIS) reflectors, and frequency selective surfaces are being developed.

[0190] Components containing the aforementioned composition can also be used for applications other than electromagnetic wave control. By reversibly changing the orientation of the liquid crystal molecules, both the dielectric constant and the refractive index can be controlled. The liquid crystal composition of the present invention exhibits high refractive index anisotropy (Δn), and therefore, based on the large amount of refractive index change and phase modulation by altering the orientation of the liquid crystal molecules under visible and infrared light, it can be controlled.

[0191] Applications for controlling these characteristics include, for example, birefringent lenses for stereoscopic image displays that switch between 2D and 3D, and liquid crystal lenses for camera focus adjustment. Additionally, they can be used in spatial light modulators (SLMs) for electronic holographic displays, or as components in lidar (Light Detection and Ranging) systems used as range sensors.

[0192] [Example]

[0193] The invention is illustrated in more detail by way of examples. The invention is not limited to these examples. The invention also includes mixtures of at least two of the compositions of the examples. The synthesized compounds were identified by nuclear magnetic resonance (NMR) analysis. The properties of the compositions were determined by the methods described below.

[0194] NMR analysis: The measuring apparatus used was a DRX-500 (manufactured by Bruker BioSpin, Inc.). 1 In the H-NMR determination, the sample was dissolved in a deuterated solvent such as CDCl3, and the determination was performed at room temperature at 500 MHz with a cumulative count of 16. Tetramethylsilane was used as an internal standard. 19 In F-NMR measurements, CFC13 was used as an internal standard, and the measurements were performed with a cumulative count of 24. In the description of nuclear magnetic resonance spectra, s refers to a singlet, d to a doublet, t to a triplet, q to a quartet, quintet, sextet, m to multiplet, and br to broad.

[0195] Test samples: When determining phase structure and transition temperature, the liquid crystal compound itself is used as the test sample. When determining the upper limit temperature, viscosity, optical anisotropy, dielectric anisotropy, and other physical properties of the nematic phase, a composition prepared by mixing the compound with the parent liquid crystal is used as the test sample.

[0196] When using a sample obtained by mixing the compound with the parent liquid crystal, the determination is performed using the following method. A sample is prepared by mixing 20 wt% of the compound with 80 wt% of the parent liquid crystal. Based on the measured value of the sample, an extrapolated value is calculated using the extrapolation method expressed by the following formula, and the value is recorded. <Extrapolated value> = (100 × <Measured value of the sample> - <Weight % of parent liquid crystal> × <Measured value of parent liquid crystal>) / <Weight % of the compound>

[0197] Even when the compound to parent liquid crystal ratio is as stated, crystallization (or a smectic phase) occurs at 25°C, the ratio of compound to parent liquid crystal is varied in the order of 10 wt%:90 wt%, 5 wt%:95 wt%, and 1 wt%:99 wt% to determine the physical properties of the sample at a ratio in which no crystallization (or a smectic phase) occurs at 25°C. Furthermore, unless otherwise specified, the ratio of compound to parent liquid crystal is 20 wt%:80 wt%.

[0198] The following master liquid crystal (i) is used as the master liquid crystal. The proportion of the components of the master liquid crystal (i) is expressed as weight %

[0199]

[0200] Measurement Methods: The characteristics are measured using the methods described below. Most of these methods are either those described in the JEITA standard (JEITA·ED-2521B) reviewed and formulated by the Japan Electronics and Information Technology Industries Association (hereinafter referred to as JEITA), or modified versions thereof. In the twisted nematic (TN) element used for measurement, no thin-film transistors (TFTs) are installed.

[0201] Upper limit temperature of nematic phase (Ni; °C):

[0202] A sample is placed on a hot plate of a melting point determination apparatus including a polarizing microscope and heated at a rate of 1 °C / min. The temperature at which a portion of the sample changes from a nematic phase to an isotropic liquid is measured.

[0203] Lower limit temperature of nematic phase (T) C ;℃):

[0204] Samples containing the nematic phase were placed in glass vials and stored in freezers at 0°C, -10°C, -20°C, -30°C, and -40°C for 10 days. The liquid crystal phase was then observed. For example, if a sample remained in the nematic phase at -20°C and transformed into a crystalline or smectic phase at -30°C, the liquid crystal phase was observed. C It is recorded as <-20℃.

[0205] Viscosity (volume viscosity; η; measured at 20°C; mPa·s):

[0206] The measurement was performed using an E-type rotational viscometer manufactured by Tokyo Keiki Co., Ltd.

[0207] Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s):

[0208] The measurements were performed according to the method described in M. Imai et al., *Molecular Crystals and Liquid Crystals*, Vol. 259, 37 (1995). A sample was placed in a TN element with a twist angle of 0° and a unit gap (cell gap) of 5 μm between the two glass substrates. For the element, a voltage was applied in 0.5V increments within a range of 16V to 19.5V. After a 0.2-second period without voltage application, the voltage was repeatedly applied under conditions of applying only a rectangular wave (rectangular pulse; 0.2 seconds) and no voltage application (2 seconds). The peak current and peak time of the transient current generated by the applied voltage were measured. The rotational viscosity was obtained based on these measured values ​​and the calculation formula (8) described on page 40 of M. Imai et al.'s paper. The value of the dielectric constant anisotropy required in the calculation is obtained using an element that measures the rotational viscosity, and by the method described below.

[0209] Refractive index anisotropy (Δn < 0.30; measured at 25°C):

[0210] The refractive index n was measured using light with a wavelength of 589 nm and an Abbe refractometer with a polarizing plate mounted on the eyepiece. The surface of the main prism was rubbed in one direction before the sample was dropped onto it. ∥ The measurement is taken when the direction of polarization is parallel to the direction of friction. Refractive index n ⊥ The measurement is taken when the direction of polarization is perpendicular to the direction of friction. The value of refractive index anisotropy is based on Δn = n ∥ -n ⊥ We use the formula to calculate.

[0211] Refractive index anisotropy (Δn ≥ 0.30; measured at 25°C):

[0212] A sample was placed in an element comprising two glass substrates and oriented in an anti-parallel configuration. The thickness retardation (Rth) of the element was measured using a phase retardation film-optical material inspection apparatus (manufactured by Otsuka Electronics Co., Ltd., trade name: RETS-100). The refractive index anisotropy (Δn) was calculated based on the retardation value (Rth) and the spacing between the glass substrates (d: unit cell gap) using the following formula. The wavelength of the light used was 589 nm.

[0213] Rth=Δn·d

[0214] Dielectric constant anisotropy (Δε; measured at 25°C):

[0215] A sample was placed in a TN element with a 9 μm gap (cell spacing) between two glass substrates and a twist angle of 80 degrees. A sinusoidal wave (10V, 1kHz) was applied to the element, and the dielectric constant (ε) along the long axis of the liquid crystal molecules was measured after 2 seconds. ∥ A sinusoidal wave (0.5V, 1kHz) was applied to the device, and the dielectric constant (ε) of the liquid crystal molecules along the short axis was measured after 2 seconds. ⊥ The value of dielectric anisotropy is based on Δε = ε ∥ -ε ⊥ We use the formula to calculate.

[0216] Voltage retention rate (VHR; measured at 25°C; %):

[0217] The unit used in the measurement had the following structure: Indium tin oxide (ITO) electrodes and rubbed polyimide alignment films were sequentially arranged on each substrate. The two substrates were bonded together with the alignment film surface as the inner side, with the angle between the upper and lower substrates being 90 degrees from the rubbing direction. The spacing between the two glass substrates (unit gap) was 5 μm. A liquid crystal composition was encapsulated in the unit. A pulsed voltage (5V for 60 microseconds) was applied to the TN element for charging. The decaying voltage was measured using a high-speed voltmeter over a period of 16.7 milliseconds, and the area A between the voltage curve per unit period and the horizontal axis was calculated. Area B represents the area before decay. The voltage retention rate is expressed as a percentage of area A relative to area B.

[0218] Dielectric constant anisotropy at 28 GHz (measured at room temperature):

[0219] Regarding the dielectric anisotropy at 28 GHz (Δε@28 GHz), the method disclosed in *Applied Optics*, Vol. 44, No. 7, p1150 (2005) was used. Liquid crystal was filled into a variable short-circuit waveguide with a window material and held in a static magnetic field of 0.3 T for 3 minutes. A 28 GHz microwave was input into the waveguide, and the amplitude ratio of the reflected wave to the incident wave was measured. The direction of the static magnetic field and the length of the short-circuit were varied for further measurements, and the refractive index (n: ne, no) and loss parameters (α: αe, αo) were determined.

[0220] The calculated refractive index, loss parameters, and the following relationship are used in the calculation of the complex permittivity (ε', ε").

[0221] ε'=n 2 -κ 2

[0222] ε”=2nκ

[0223] α=2ωκ / c

[0224] Here, c is the speed of light in vacuum, ω is the angular velocity, and κ is the extinction coefficient. ε' is calculated from ne. ∥ ε' is calculated based on no. ⊥ The dielectric anisotropy (Δε@28GHz) is based on ε' ∥ -ε' ⊥ Let's calculate it.

[0225] Dielectric loss tangent (tanδ; measured at room temperature) at 28 GHz:

[0226] The dielectric loss tangent (tanδ@28GHz) at 28GHz is calculated using the complex permittivity (ε', ε”) and based on ε” / ε'. Since tanδ also exhibits anisotropy, a larger value is recorded.

[0227] [Example 1]

[0228] Synthesis of compounds (1-6): 4-((2,5-difluoro-4-isothiocyanate-phenyl)ethynyl)-3-fluoro-4'-(4-pentylcyclohexyl)-1,1'-biphenyl

[0229]

[0230]

[0231] Commercially available raw materials, 1-bromo-3-fluoro-4-iodobenzene (50 g), triethylamine (150 mL), and tetrahydrofuran (THF) (100 mL), were transferred to a reaction vessel. A THF solution of 15.1 g of 2-methyl-3-butyn-2-ol (50 mL) was transferred to a dropping funnel, which was then placed in the reaction vessel and purged with nitrogen. CuI (0.6 g) and PdCl2(PPh3)2 (1.2 g) were added as catalysts. The mixture was stirred at room temperature, and the addition was started simultaneously. After the addition was complete, the mixture was stirred at room temperature for 2 hours. Pure water, ammonium chloride, and toluene were added to the reaction solution. The organic layer was washed twice with pure water and concentrated. The organic layer was purified by silica gel column chromatography (developing solvent: toluene) and recrystallized from heptane to obtain intermediate 1 (40.7 g).

[0232] The structure of the obtained compound was confirmed by NMR determination.

[0233] 1 H-NMR (δppm: CDCl3): 7.28~7.21 (m, 3H), 2.24 (s, 1H), 1.63 (s, 6H).

[0234]

[0235] Under nitrogen atmosphere, Pd-132 (Johnson Matthey) (1.0 g) was added to 4,4,5,5-tetramethyl-2-(4-(4-pentylcyclohexyl)phenyl)-1,3,2-dioxaborane (50 g), intermediate 1 (36.1 g), potassium carbonate (38.8 g), toluene (350 mL), ethanol (150 mL), and purified water (150 mL). The mixture was heated and stirred at 80 °C for 1 hour. After cooling to room temperature, purified water and toluene were added, and the organic layer was washed with purified water. The mixture was then concentrated, and the obtained solid was purified by silica gel column chromatography (developing solvent: toluene). Recrystallization was performed from boiling toluene / heptane = 4 / 6 (volume ratio) to obtain intermediate 2 (44 g).

[0236] The structure of the obtained compound was confirmed by NMR determination.

[0237] 1 H-NMR (δppm: CDCl3): 7.49 (d, 2H), 7.44 (t, 1H), 7.33~7.27 (m, 4H), 2.51 (tt, 1H), 2.08 (s, 1H), 1.90 (m, 4H), 1.65 (s, 6H), 1.47 (m, 2H), 1.37~1.20 (m, 9H), 1.06 (m, 2H), 0.90 (t, 3H).

[0238]

[0239] Under nitrogen atmosphere, KOH (6.7 g) was added to intermediate 2 (44 g) and toluene (440 mL), and the mixture was heated and stirred at 120 °C for 2 hours. After cooling to room temperature, the mixture was neutralized with dilute hydrochloric acid, and the organic layer was washed twice with pure water and concentrated. The obtained solid was purified by silica gel column chromatography (developing solvent: toluene / heptane = 1 / 9 (volume ratio)) and recrystallized from heptane to obtain intermediate 3 (29 g).

[0240] The structure of the obtained compound was confirmed by NMR determination.

[0241] 1 H-NMR (δppm: CDCl3): 7.51 (t, 1H), 7.49 (d, 2H), 7.34~7.28 (m, 4H), 3.34 (s, 1H), 2. 51(tt, 1H), 1.91(m, 4H), 1.48(m, 2H), 1.37~1.20(m, 9H), 1.06(m, 2H), 0.90(t, 3H).

[0242]

[0243] Under nitrogen atmosphere, CuI (0.07 g) and Pd(PPh3)4 (0.22 g) were added to 2,5-difluoro-4-iodoaniline (4.5 g), intermediate 3 (7 g), triethylamine (20 mL), and THF (20 mL), and the mixture was heated and stirred at 40 °C for 1 hour. Pure water, ammonium chloride, and toluene were added to the reaction solution, and the organic layer was washed twice with pure water and concentrated. Purification was performed using silica gel column chromatography (developing solvent: toluene), recrystallizing from toluene / heptane = 15 / 85 (volume ratio) to obtain intermediate 4 (8.9 g).

[0244] The structure of the obtained compound was confirmed by NMR determination.

[0245] 1 H-NMR (δppm: CDCl3): 7.53 (t, 1H), 7.51 (d, 2H), 7.35 (dd, 1H), 7.32 (dd, 1H), 7.29 (d, 2H), 7.14 (dd, 1H), 6.50 (dd, 1H), 4.03 (s, 2H), 2.51 (tt, 1H), 1.90 (m, 4H), 1.47 (m, 2H), 1.37~1.20 (m, 9H), 1.06 (m, 2H), 0.90 (t, 3H).

[0246]

[0247] Intermediate 4 (8.9 g), 1,1'-thiocarbonyldiimidazole (10 g), and THF (70 mL) were heated and stirred at 80 °C for 1 hour. The reaction solution was concentrated and purified by silica gel column chromatography (developing solvent: toluene / heptane = 2 / 8 (volume ratio)). Recrystallization from boiling heptane yielded compounds (1-6): 4-((2,5-difluoro-4-isothiocyanate-phenyl)ethynyl)-3-fluoro-4'-(4-pentylcyclohexyl)-1,1'-biphenyl.

[0248] The structure of the obtained compound was confirmed by NMR determination.

[0249] 1 H-NMR (δppm: CDCl3): 7.56 (t, 1H), 7.52 (d, 2H), 7.38 (dd, 1H), 7.34~7.29 (m, 4H), 6.94 (dd, 1H), 2.52(tt, 1H), 1.91(m, 4H), 1.48(m, 2H), 1.37~1.20(m, 9H), 1.07(m, 2H), 0.90(t, 3H).

[0250] [Example 2]

[0251] Synthesis of compounds (1-8): 3-Fluoro-4-((5-fluoro-4-isothiocyanate-2-methylphenyl)ethynyl)-4'-(4-propylcyclohexyl)-1,1'-biphenyl

[0252]

[0253] The compounds represented by formulas (1-8) were synthesized using the same method as described in the synthesis examples.

[0254] The structure of the obtained compound was confirmed by NMR determination.

[0255] 1 H-NMR (δppm: CDCl3): 7.53 (t, 1H), 7.52 (d, 2H), 7.38 (dd, 1H), 7.34 (dd, 1H), 7.30 (d, 2H), 7.29 (d, 1H), 7.05 (d, 1H), 2.52 (tt, 1H), 2.46 (s, 3H), 1.90 (m, 4H), 1.48 (m, 2H), 1.40~1.20 (m, 5H), 1.07 (m, 2H), 0.91 (t, 3H).

[0256] [Example 3]

[0257] Synthesis of compounds (1-5): 4-((3,5-difluoro-4-isothiocyanate-phenyl)ethynyl)-2-fluoro-5-methyl-4'-(4-pentylcyclohexyl)-1,1'-biphenyl

[0258]

[0259] The compounds represented by formulas (1-5) were synthesized using the same method as described in the synthesis examples.

[0260] The structure of the obtained compound was confirmed by NMR determination.

[0261] 1 H-NMR (δppm: CDCl3): 7.48 (dd, 2H), 7.31~7.28 (m, 3H), 7.24 (d, 1H), 7.12 (d, 2H), 2.51 (tt , 1H), 2.48 (s, 3H), 1.91 (m, 4H), 1.48 (m, 2H), 1.37~1.20 (m, 9H), 1.07 (m, 2H), 0.90 (t, 3H).

[0262] [Example 4]

[0263] Synthesis of compounds (1-10): 1-Fluoro-2-((4-isothiocyanate-phenyl)ethynyl)-4-methyl-5-((4-(4-pentylcyclohexyl)phenyl)ethynyl)benzene

[0264]

[0265] The compounds represented by formulas (1-10) were synthesized using the same method as described in the synthesis examples.

[0266] The structure of the obtained compound was confirmed by NMR determination.

[0267] 1 H-NMR (δppm: CDCl3): 7.52 (d, 2H), 7.45 (d, 2H), 7.34 (d, 1H), 7.23~7.20 (m, 5H), 2.49 (tt, 1H), 2.45(s, 3H), 1.89(m, 4H), 1.45(m, 2H), 1.36~1.20(m, 9H), 1.05(m, 2H), 0.90(t, 3H).

[0268] The compounds in the examples are indicated by symbols based on the definitions in Table 2. The numbers in parentheses following the symbols correspond to the compound numbers. The symbol (-) indicates other liquid crystal compounds. The proportion (percentage) of liquid crystal compounds is a weight percentage (wt%) based on the weight of the liquid crystal composition. Finally, the characteristic values ​​of the compositions are summarized.

[0269] Table 2. Representation of compounds using notations

[0270] R-(A1)-Z1-……-Z n -(A n )-R'

[0271]

[0272] [Comparative Example 1] Liquid Crystal Composition C1

[0273]

[0274] NI = 101.2℃; T C <-40℃; Δn=0.471; Δε=14.6

[0275] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition C1 at 28GHz are as follows.

[0276] Δε@28GHz=1.27

[0277] tanδ@28GHz=0.006

[0278] [Example 5] Liquid crystal composition M1

[0279]

[0280] NI = 155.1℃; T C <-40℃; Δn=0.509; Δε=15.7

[0281] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M1 at 28GHz are as follows.

[0282] Δε@28GHz=1.32

[0283] tanδ@28GHz=0.006

[0284] Compound (1) was added to Comparative Example 1, and the composition containing compounds (1) to (3) corresponds to Example 5. Here, the Δε@28GHz of the composition of Comparative Example 1 is 1.27, while the Δε@28GHz of the composition of Example 5 is 1.32, which can be considered large. The tanδ@28GHz is 0.006, which is small. Moreover, the upper limit temperature of Comparative Example 1 is 101.2°C and the lower limit temperature is <-40°C, while the upper limit temperature of Example 5 is 155.1°C and the lower limit temperature is <-40°C. It was confirmed that when compound (1) is applied, a liquid crystal composition having a nematic phase over a wider temperature range can be obtained.

[0285] [Example 6] Liquid crystal composition M2

[0286]

[0287]

[0288] NI = 154.2℃; T C <-30℃; Δn=0.506; Δε=15.9

[0289] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M2 at 28GHz are as follows.

[0290] Δε@28GHz=1.32

[0291] tanδ@28GHz=0.007

[0292] [Example 7] Liquid crystal composition M3

[0293]

[0294] NI = 147.5℃; T C <-30℃; Δn=0.494; Δε=15.8

[0295] The dielectric anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M3 at 28GHz are as follows.

[0296] Δε@28GHz=1.30

[0297] tanδ@28GHz=0.006

[0298] [Example 8] Liquid Crystal Composition M4

[0299]

[0300] NI = 125.1℃; T C <-40℃; Δn=0.478; Δε=12.6

[0301] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M4 at 28GHz are as follows.

[0302] Δε@28GHz=1.28

[0303] tanδ@28GHz=0.006

[0304] [Example 9] Liquid Crystal Composition M5

[0305]

[0306] NI = 120.0℃; T C <-40℃; Δn=0.485; Δε=11.9

[0307] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M5 at 28GHz are as follows.

[0308] Δε@28GHz=1.23

[0309] tanδ@28GHz=0.006

[0310] [Example 10] Liquid Crystal Composition M6

[0311]

[0312] NI = 148.1℃; T C <-30℃; Δn=0.488; Δε=16.8

[0313] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M6 at 28GHz are as follows.

[0314] Δε@28GHz=1.31

[0315] tanδ@28GHz=0.007

[0316] [Example 11] Liquid Crystal Composition M7

[0317]

[0318] NI = 145.6℃; T C <-30℃; Δn=0.490; Δε=16.1

[0319] The dielectric constant anisotropy (Δε@28GHz) and dielectric loss tangent (tanδ@28GHz) of the liquid crystal composition M7 at 28GHz are as follows.

[0320] Δε@28GHz=1.34

[0321] tanδ@28GHz=0.006

[0322] The compositions of Examples 5 to 11 each contain compound (1) to compound (3). The liquid crystal compositions containing compound (1) to compound (3) can reduce the value of tanδ@28GHz while maintaining the basic properties of a liquid crystal composition and keeping Δε@28GHz high. In particular, the liquid crystal composition containing compound (1) has a very high upper temperature while maintaining a low lower limit temperature.

[0323] Regarding the required characteristics of the liquid crystal composition, it is required that in the frequency region used for phase control, there be a large dielectric constant anisotropy (Δε) enabling large phase control and a small dielectric loss tangent (tanδ) proportional to the absorbed energy of the electromagnetic wave signal of the liquid crystal composition. Based on the results of examples and comparative examples, it has been demonstrated that the composition of the present invention has a large dielectric constant anisotropy (Δε@28GHz) and a small dielectric loss tangent (tanδ@28GHz). Generally, if tanδ is small, the absorbed energy of the electromagnetic wave becomes low. Therefore, the liquid crystal composition using the compound represented by formula (1) can reduce the absorbed energy of the electromagnetic wave signal, and the loss of the electromagnetic wave signal can be set even lower. Based on the above, it can be concluded that the liquid crystal composition of the present invention can transmit electromagnetic wave signals more efficiently.

[0324] [Industry availability]

[0325] The liquid crystal compound of the present invention provides a liquid crystal compound that satisfies at least one of the properties of compounds such as thermal stability, high transparency, very large refractive index anisotropy, and excellent compatibility with other liquid crystal compounds. Compositions containing the compound of the present invention can simultaneously satisfy at least one of the characteristics of compositions such as large dielectric constant anisotropy (large refractive index anisotropy), small dielectric loss tangent (tanδ), and large dielectric constant anisotropy at low frequencies for reducing driving voltage, while having both a high upper limit temperature and a low lower limit temperature of the nematic phase. Furthermore, a more preferred liquid crystal composition can be provided that satisfies at least one of the characteristics of compositions such as low viscosity, large specific resistivity in the driving frequency region, and thermal stability. Elements containing said composition can be used for the control of electromagnetic wave signals in the frequency range of 1 GHz to 10 THz.

Claims

1. A liquid crystal compound, which is a compound represented by formula (1); In equation (1), R 1 It is hydrogen, halogen or alkyl having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen; L 1 L 2 L 3 and L 4 It can be hydrogen, fluorine, chlorine, methyl, or ethyl; Y 1 and Y 2 It can be hydrogen, fluorine, or chlorine; n is 0 or 1; in, When n is 0, L does not exist. 1 L 2 L 3 and L 4 The case where any two of them are methyl and the remaining two are hydrogen, fluorine, chlorine or ethyl.

2. The liquid crystal compound according to claim 1, wherein, The compound represented by formula (1) can be any one of formulas (1-1) to (1-18); In equations (1-1) to (1-18), R 1' It is an alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen; L 1' It is fluorine or methyl, L 2' It can be hydrogen, fluorine, or methyl; Y 1' It is hydrogen or fluorine; In equations (1-1), (1-2), (1-5), (1-6), and (1-9), L does not exist. 1' and L 2' The case where it is also methyl; In equations (1-3), (1-4), (1-7), and (1-8), L does not exist. 1' and L 2' The case where only one of them is methyl.

3. A liquid crystal composition comprising at least one liquid crystal compound as described in claim 1 or 2.

4. The liquid crystal composition according to claim 3, further comprising at least one compound selected from the compounds represented by formula (2) and formula (3); In equations (2) and (3), R 2 and R 3 It is a hydrogen, halogen or a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -CH2- may be substituted with -O- or -S-, at least one -(CH2)2- may be substituted with -CH=CH- or -C≡C-, and in these groups at least one hydrogen may be substituted with a halogen; L 21 L 22 L 23 L 31 L 32 and L 33 It is hydrogen, halogen, alkyl with 1 to 3 carbon atoms, fluorinated alkyl with 1 to 3 carbon atoms, or cycloalkyl with 3 to 5 carbon atoms; Y 21 Y 31 Y 32 Y 33 Y 34 Y 35 and Y 36 It is hydrogen or halogen.

5. The liquid crystal composition according to claim 4, wherein it contains at least one compound selected from the group consisting of compounds represented by formulas (2-1) to (2-10) as the compound represented by formula (2); In equations (2-1) to (2-10), R 2' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-.

6. The liquid crystal composition according to claim 4, wherein it contains at least one compound selected from the group consisting of compounds represented by formulas (3-1) to (3-11) as the compound represented by formula (3); In equations (3-1) to (3-11), R 3' It is a straight-chain alkyl group having 1 to 12 carbon atoms, wherein at least one -(CH2)2- may be substituted by -CH=CH- or -C≡C-; Y 35' It can be hydrogen, fluorine, or chlorine.

7. The liquid crystal composition according to claim 4, wherein, Based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) ranges from 5% to 25% by weight, and the proportion of the compound represented by formula (2) ranges from 10% to 55% by weight.

8. The liquid crystal composition according to claim 4, wherein, Based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) ranges from 5% to 25% by weight, and the proportion of the compound represented by formula (3) ranges from 20% to 50% by weight.

9. The liquid crystal composition according to claim 4, wherein, Based on the weight of the liquid crystal composition, the proportion of the compound represented by formula (1) is in the range of 5% to 25% by weight, the proportion of the compound represented by formula (2) is in the range of 10% to 55% by weight, and the proportion of the compound represented by formula (3) is in the range of 20% to 50% by weight.

10. The liquid crystal composition according to claim 3, wherein, The refractive index anisotropy at 25℃ with a wavelength of 589nm is greater than 0.

40.

11. The liquid crystal composition according to claim 3, wherein, The dielectric constant anisotropy at 25°C and a frequency of 1 kHz is greater than 10.

12. The liquid crystal composition according to claim 3, wherein, The dielectric constant anisotropy at 25°C is in the range of 1.0 to 3.0 within at least one frequency range from 1 GHz to 10 THz.

13. The liquid crystal composition according to claim 3, wherein it comprises an optically active compound.

14. The liquid crystal composition according to claim 3, wherein it comprises a polymerizable compound.

15. The liquid crystal composition according to claim 3, further comprising at least one of an antioxidant, an ultraviolet absorber, an antistatic agent, and a dichroic pigment.

16. An element comprising the liquid crystal composition of claim 3, wherein the element is configured to reversibly control the conversion of dielectric constant by reversibly changing the orientation of liquid crystal molecules.

17. An element comprising the liquid crystal composition of claim 3 and for electromagnetic wave control in a frequency range of 1 GHz to 10 THz.

18. A liquid crystal lens comprising the liquid crystal composition as described in claim 3.

19. A birefringent lens for stereoscopic image display, comprising the liquid crystal composition as described in claim 3.

20. An optical modulation element comprising the liquid crystal composition as described in claim 3.

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