Liquid crystal compound, liquid crystal composition and application thereof

Abstract

The embodiment of the invention provides a liquid crystal compound, a liquid crystal composition and application thereof. The compound comprises at least three Ar rings and one substituted or unsubstituted thiophene ring arranged in a linear manner, and a linking group connected between two Ar rings or between Ar rings and substituted or unsubstituted thiophene ring, where Ar rings represent substituted or unsubstituted benzene rings; the liquid crystal compound is characterized in that the Ar ring disposed at the end of the molecular chain of the liquid crystal compound independently has one substituent selected from the group consisting of a halogenated or unsubstituted linear alkyl group, a halogenated or unsubstituted linear alkoxy group, a halogenated or unsubstituted chain alkenyl group, and a halogenated or unsubstituted chain alkenyloxy group. When the compound is added into the liquid crystal composition, the low-temperature stability of the liquid crystal composition can be improved, the clearing point of the liquid crystal composition can be reduced, and the light stability and the heat stability of the liquid crystal composition can be enhanced under the condition of keeping high birefringence.

Description

Technical Field

[0001] The present application relates to the technical field of liquid crystal materials, and in particular to a liquid crystal compound, a liquid crystal composition and applications thereof. Background Art

[0002] Liquid crystal materials, due to their tunable electro-optical properties, have led to the widespread application of liquid crystal devices in fields such as displays and communications. With the advancement of technology, the requirements for liquid crystal devices are becoming increasingly stringent, placing higher demands on the liquid crystal materials they use, such as high birefringence, low viscosity, and good low-temperature stability. However, a single liquid crystal material cannot meet all these performance requirements, so blending liquid crystal materials has become a research focus for major liquid crystal manufacturers. However, existing liquid crystal compositions, which combine multiple liquid crystal compounds, cannot effectively balance these various properties.

[0003] Currently, the mainstream approach to obtaining high-birefringence liquid crystal materials in the industry is to use liquid crystal compositions containing isothiocyanates or benzylene compounds. However, isothiocyanate-based liquid crystal compositions generally have poor low-temperature stability, while benzylene-based liquid crystal compositions have high viscosity and poor low-temperature stability. Therefore, there is a need to provide a liquid crystal composition that balances high birefringence with low viscosity and good low-temperature stability. Summary of the Invention

[0004] In view of this, the embodiments of the present application provide a liquid crystal compound, a liquid crystal composition and its application. The molecular structure of the liquid crystal compound contains a thiophene ring. The liquid crystal composition using it can simultaneously take into account a higher birefringence, a lower viscosity, a suitable clearing point and good light / thermal stability, etc., thereby obtaining a liquid crystal device with better performance.

[0005] In a first aspect, an embodiment of the present application provides a liquid crystal compound, comprising at least three Ar rings and one substituted or unsubstituted thiophene ring arranged in a linear manner, and a connecting group connected between two of the Ar rings or between the Ar ring and the substituted or unsubstituted thiophene ring, wherein the Ar ring represents a substituted or unsubstituted benzene ring; and the Ar ring arranged at the end of the molecular chain of the liquid crystal compound independently has a substituent selected from a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, and a halogenated or unsubstituted chain alkenyloxy group.

[0006] The liquid crystal compound has a substituted or unsubstituted thiophene ring at one end of the molecular chain or in the middle of the molecular chain. When added to a liquid crystal composition, it can appropriately disrupt the regular arrangement of the liquid crystal molecules, thereby reducing its clearing point and room temperature viscosity while ensuring a high birefringence of the liquid crystal composition, and improving its low-temperature stability, thereby facilitating the application of the liquid crystal composition in liquid crystal devices.

[0007] In the embodiment of the present application, the linking groups are independently selected from one or more of a straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-. These linking groups can ensure that the liquid crystal composition is easier to prepare.

[0008] In some embodiments of the present application, the liquid crystal compound has any one of the following general formulas: (I-A), (I-B), and (I-C):

[0009]

[0010]

[0011] wherein R1 and R2 are each independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, and halogenated or unsubstituted chain alkenyloxy;

[0012] X1~X 14 Each occurrence is independently selected from a hydrogen atom (H), a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group, and at least one of X3 and X4 is a hydrogen atom. In formula (I-B), X 11 With X 12 At least one of them is a hydrogen atom;

[0013] Each occurrence of Z1, Z2, and Z3 is independently selected from one of a straight-chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-; and Z1, Z2, and Z3 are not straight-chain single bonds at the same time.

[0014] The liquid crystal compound having any of the structures of formula (I-A), formula (I-B), and formula (I-C) above has a stable structure and can help improve the low-temperature stability and birefringence of the liquid crystal composition to which it is added, and moderately reduce the clearing point.

[0015] In the embodiment of the present application, the halogenated or unsubstituted linear alkyl group is a fluorinated or unsubstituted C1-C10 Straight-chain alkyl; the halogenated or unsubstituted straight-chain alkoxy is a fluorinated or unsubstituted C1~C 10 Straight chain alkoxy; the halogenated or unsubstituted chain alkenyl is a fluorinated or unsubstituted C2~C 10 Chain alkenyl; the halogenated or unsubstituted chain alkenyloxy is a fluorinated or unsubstituted C2~C 10 Chain alkenyloxy; the unsubstituted cycloalkyl is an unsubstituted C3~C 10 Cycloalkyl.

[0016] Each group has a suitable number of carbon atoms, which not only makes the raw materials for preparing the compounds of formula (I), formula (II) and formula (III) easily available, but also ensures that the composition formed by mixing them has good liquid crystal properties.

[0017] In some embodiments of the present application, in the formula (I-A), formula (I-B), and formula (I-C), at least one of X1 and X3 is a hydrogen atom, and at least one of X2 and X4 is a hydrogen atom; in the formula (I-B), X9 and X 11 At least one of them is a hydrogen atom; X 10 With X 12 At least one of them is a hydrogen atom. This can avoid introducing too many substituents into the molecular structure of the same liquid crystal compound, thereby maintaining its rod-like structure and making it still have liquid crystal properties.

[0018] In some embodiments of the present application, in formula (I-A), X4 is a hydrogen atom and Z1 is a linear single bond; alternatively, X4 is a hydrogen atom and Z2 is a linear single bond; alternatively, X3 is a hydrogen atom and Z3 is a linear single bond. In this case, the substance represented by formula (I-A) having three substituted or unsubstituted benzene rings and a thiophene ring attached to one end is easier to synthesize, and the liquid crystal composition containing it has a more significant effect on reducing the clearing point.

[0019] In some embodiments of the present application, in formula (I-B), X4, X 12 are all hydrogen atoms, Z1 is a straight chain single bond; or, X4, X 12 are all hydrogen atoms, Z2 is a straight chain single bond; or, X 11 , X3 is a hydrogen atom, and Z3 is a linear single bond. In this case, the substance represented by formula (I-B) is easier to synthesize.

[0020] In some embodiments of the present application, in formula (I-C), X4 is a hydrogen atom and Z3 is a linear single bond. In this case, the material represented by formula (I-C) is relatively easy to synthesize, and the polyaromatic material having five substituted or unsubstituted benzene rings and one thiophene ring in the molecular structure still exhibits good liquid crystal properties.

[0021] A second aspect of the embodiments of the present application provides a liquid crystal composition, which includes at least one liquid crystal compound as described in the first aspect of the embodiments of the present application.

[0022] By introducing the liquid crystal compound provided in the first aspect of the present application into a liquid crystal composition, the birefringence of the liquid crystal composition can be improved, while its viscosity and clearing point can be reduced, and its low-temperature stability, as well as its light and thermal stability can be improved by utilizing the irregular rod-shaped conjugated molecular structure of the liquid crystal compound. As a result, a liquid crystal device with good performance such as faster response time and stronger low-temperature resistance can be obtained by using the liquid crystal composition.

[0023] In the embodiment of the present application, the total mass percentage of the liquid crystal compound in the liquid crystal composition is in the range of 0.01%-60%. Adding an appropriate amount of the first liquid crystal compound helps it fully exert the above-mentioned effects, thereby improving the overall performance of the liquid crystal composition.

[0024] In the embodiment of the present application, the liquid crystal composition further includes one or more second liquid crystal compounds represented by the following formula (II-1), formula (II-2), formula (II-3), and formula (II-4):

[0025]

[0026] Among them, R a 、R b Each occurrence of R is independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, halogenated or unsubstituted chain alkenyloxy, and substituted or unsubstituted cycloalkyl; c One selected from the group consisting of a fluorine atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and a substituted or unsubstituted cycloalkyl group;

[0027] X 1 ~X 11 Each occurrence is independently selected from one of a hydrogen atom, a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted straight-chain alkylthio group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group;

[0028] Z 1 、Z 2Independently selected from one of a straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-; in formula (Ⅱ-4), m is 0 or 1.

[0029] The above-mentioned liquid crystal composition contains both the specific liquid crystal compound provided in the first aspect of the present application and the second liquid crystal composition. The liquid crystal composition can better balance higher birefringence, lower viscosity, suitable clearing point, lower crystallization point, wider nematic phase temperature range, high dielectric anisotropy, and higher optical, thermal and chemical stability, and has greater application prospects.

[0030] In some embodiments of the present application, in the formula (II-1), formula (II-2), formula (II-3), and formula (II-4), X 4 With X 6 At least one of them is a hydrogen atom; in the formula (II-1) and formula (II-2), X 1 With X 3 At least one of them is a hydrogen atom, X 7 With X 9 At least one of them is a hydrogen atom; in the formula (II-1), X 10 With X 12 At least one of them is a hydrogen atom. This helps to ensure that the substance represented by formula (II-1), formula (II-2), formula (II-3) or formula (II-4) basically maintains a rod-like structure, so that it has good liquid crystal properties.

[0031] In the embodiment of the present application, the R a 、R b 、R c In the embodiment, the substituents in the substituted cycloalkyl group include one or more of a halogenated or unsubstituted linear alkyl group, a halogenated or unsubstituted linear alkoxy group, a halogenated or unsubstituted linear alkenyl group, a halogenated or unsubstituted linear alkenyloxy group, and an alkyl-substituted or unsubstituted cycloalkyl group. The introduction of various substituents can enrich the variety of the second liquid crystal compound, obtain compound products with slightly different properties, and better realize applications.

[0032] In some embodiments of the present application, the weight percentage of the second liquid crystal compound in the liquid crystal composition is within a range of 0.5% to 78%. Adding an appropriate amount of the second liquid crystal compound to the liquid crystal compound provided in the first aspect of the present application can ensure that the liquid crystal composition containing the second liquid crystal compound exhibits excellent liquid crystal properties, strong fluidity, and a high birefringence.

[0033] In some embodiments of the present application, the mass percentage of the second liquid crystal compound in the liquid crystal composition is greater than the mass percentage of the liquid crystal compound provided in the first aspect of the embodiment of the present application. This is more conducive to the liquid crystal composition having a higher birefringence and low-temperature stability.

[0034] In some embodiments, in the liquid crystal composition, the total mass percentage of the liquid crystal compound is 1%-30%, and the total mass percentage of the second liquid crystal compound is 40%-78%. In this case, the overall performance of the liquid crystal composition is better.

[0035] In some embodiments of the present application, the liquid crystal composition further includes additives, including one or more of a UV absorber, a UV stabilizer, an antioxidant, and a voltage stabilizer. The presence of the additives can help improve one or more of the UV resistance, high-temperature stability, and chemical oxidation resistance of the liquid crystal composition. The additives can be added as needed.

[0036] In the embodiments of the present application, the additive is present in the liquid crystal composition in an amount ranging from 0.01% to 10% by weight. The appropriate amount of the additive can effectively improve the liquid crystal composition's resistance to light, heat, and chemical oxidation, while not significantly affecting the composition's birefringence and viscosity.

[0037] In the embodiments of the present application, the liquid crystal composition has a birefringence of 0.34 or greater, a clearing point in the range of 110-140°C, a crystallization point below -30°C, and a viscosity in the range of 450-750 mPa·s at 25°C. This liquid crystal composition has a high birefringence, a low clearing point, low room temperature viscosity, and resistance to crystallization at low temperatures, resulting in excellent overall performance and greater ease of application.

[0038] The third aspect of the present invention provides the use of the liquid crystal compound provided in the first aspect of the present invention or the liquid crystal composition provided in the second aspect of the present invention in a liquid crystal device. The liquid crystal compound and liquid crystal composition can be used in the liquid crystal layer of the liquid crystal device to improve the performance and reliability of the liquid crystal device.

[0039] A fourth aspect of the embodiments of the present application provides a liquid crystal device, which includes a liquid crystal layer, and the liquid crystal layer includes the liquid crystal compound provided in the first aspect of the present application, or the liquid crystal composition provided in the second aspect of the embodiments of the present application.

[0040] In an embodiment of the present application, the liquid crystal device includes a silicon-based backplane, a cover plate with a transparent electrode layer, and the liquid crystal layer disposed between the silicon-based backplane and the cover plate with the transparent electrode layer. In this case, the liquid crystal device may be an LCoS device.

[0041] The fifth aspect of the embodiments of the present application provides the application of the liquid crystal device as described in the fourth aspect of the embodiments of the present application in wavelength selection switches, microwave scanning antennas, liquid crystal antennas, liquid crystal optical waveguides, dynamic focusing lenses, liquid crystal gratings, lidar, beam tracking, projection, flat panel displays, holographic displays, optical communications, and wireless communications.

[0042] A sixth aspect of the present application provides a device comprising the liquid crystal device described in the fourth aspect of the present application. The device includes, but is not limited to, one or more of a wavelength selective switch, a microwave scanning antenna, a liquid crystal antenna, a liquid crystal optical waveguide, a dynamic focusing lens, a liquid crystal grating, a laser radar, a beam tracker, a projector, a flat panel display, a holographic display, an optical communication device, a wireless communication device, and the like.

[0043] Based on the good performance of the above-mentioned liquid crystal device, the performance of various devices including the liquid crystal device is also relatively good, and the market competitiveness is outstanding. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic structural diagram of a liquid crystal device provided in an embodiment of the present application.

[0045] Figure 2 A schematic diagram of the structure of a wavelength selective switch provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0047] Liquid crystal materials have adjustable electro-optical properties, and liquid crystal devices made with them are widely used in display, optical communications, wireless communications, laser detection, and other fields. Examples include automotive displays, laser projection, wavelength selective switches (WSS), and lidar. Liquid crystal devices made with liquid crystal on silicon (LCoS) technology (also known as LCoS devices) are particularly widely used. Figure 1 A schematic diagram of the structure of a liquid crystal device provided in an embodiment of the present application. In some embodiments, Figure 1 The liquid crystal device shown may specifically be an LCoS device, which may be used in WSS, etc., and may serve as an optical switching engine of the WSS to implement phase modulation.

[0048] See Figure 1 The liquid crystal device 100 includes a cover plate 10 with a transparent electrode layer, a silicon-based back plate 20, and a liquid crystal layer 30 disposed therebetween. The liquid crystal layer 30 includes a plurality of liquid crystal molecules ( Figure 1 Liquid crystal molecules can be deflected under certain voltage conditions to achieve phase modulation of the light beam.

[0049] The cover plate 10 may include a transparent substrate 11 and a transparent electrode layer 12 disposed on one surface thereof. The transparent substrate 11 is typically glass and serves to protect the liquid crystal layer 30, allow light signals to pass through it, and support the transparent electrode layer 12. The transparent electrode layer 12 may be an indium tin oxide (ITO) layer or an indium zinc oxide (IZO) layer, which has excellent conductivity and transparency, and is used to transmit light signals and conduct electricity.

[0050] The silicon-based backplane 20 may include a silicon substrate 21 and a reflective layer 22 stacked on one surface of the silicon substrate 21. The silicon substrate 21 may be a CMOS (Complementary Metal Oxide Semiconductor in English, Complementary Metal Oxide Semiconductor in Chinese) integrated circuit chip coated with liquid crystal silicon. Therefore, the silicon-based backplane 20 may also be referred to as a CMOS substrate. It is understandable that the silicon substrate 21 contains a control circuit. The material of the reflective layer 22 may be aluminum, which is used to improve the reflectivity of the silicon substrate 21, and the reflective layer is generally plated. In some embodiments, the silicon-based backplane 20 also includes a backplane electrode layer and a pixel array, which may be integrated in the silicon substrate 21.

[0051] In some embodiments, a first alignment layer 13 may be further provided on the side of the transparent electrode layer 12 facing away from the transparent substrate 11. A second alignment layer 23 may also be provided on the silicon-based backplane 20, specifically, the second alignment layer 23 is provided on the side of the reflective layer 22 facing away from the silicon substrate 21. When the cover plate 10 and the silicon-based backplane 20 are assembled into a liquid crystal device 100, the two are arranged opposite to each other, and the liquid crystal layer 30 is located between the first alignment layer 13 and the second alignment layer 23. In this case, the above-mentioned liquid crystal device 100 includes a transparent substrate 11, a transparent electrode layer 12, a first alignment layer 13, a liquid crystal layer 30, a second alignment layer 23, a reflective layer 22 and a silicon substrate 21, which are stacked in sequence. It should be understood that Figure 1 The sizes and positions of the various layers of the liquid crystal device 100 are for illustration only and do not constitute a limitation to the present application.

[0052] The first alignment layer 13 on the cover plate 10 and the second alignment layer 23 on the silicon-based backplane 20 can fix the alignment direction of the liquid crystal molecules in the liquid crystal layer 30 under zero voltage conditions. In some embodiments, when no voltage is applied to the liquid crystal layer 30, the first and second alignment layers 13, 23 control the parallel alignment of the liquid crystal molecules. When a certain voltage is applied between the transparent electrode layer 12 and the silicon substrate 21 via the driving circuit in the silicon-based backplane 20, the liquid crystal molecules in the liquid crystal layer 30 rotate in response to the voltage. Because liquid crystal molecules produce birefringence under the influence of an electric field, different electric field intensities can cause the liquid crystal molecules to rotate to varying degrees, thereby changing their refractive index and achieving the purpose of phase adjustment of the light beam transmitted through the liquid crystal molecules.

[0053] The liquid crystal layer 30 is generally formed by pouring a liquid crystal composition into the space between the oppositely arranged cover plate 10 and the silicon-based back plate 20, and the liquid crystal composition is usually formed by mixing a plurality of liquid crystal compounds (also known as liquid crystal monomers). However, the liquid crystal composition currently used in the liquid crystal device 100 cannot take into account a high birefringence, a low viscosity, a suitable clearing point, and good light / thermal stability, so that the device performance of the liquid crystal device cannot effectively meet the requirements of practical applications. To this end, the embodiments of the present application provide a liquid crystal composition with excellent comprehensive performance that can be used in the above-mentioned liquid crystal device 100 and its related applications.

[0054] First, an embodiment of the present application provides a liquid crystal compound that can be used in a liquid crystal composition. The liquid crystal compound has a substituted or unsubstituted thiophene ring at one end of the molecular chain or in the middle of the molecular chain. When the liquid crystal compound is added to the liquid crystal composition, the clearing point can be moderately reduced, the room temperature viscosity can be reduced, and the low-temperature stability can be improved while ensuring a high birefringence of the liquid crystal composition.

[0055] Specifically, the liquid crystal compound provided in the embodiment of the present application includes at least three Ar rings and one substituted or unsubstituted thiophene ring arranged in a linear manner, and a connecting group connected between two of the Ar rings or between the Ar ring and the substituted or unsubstituted thiophene ring, wherein the Ar ring represents a substituted or unsubstituted benzene ring; and the Ar ring arranged at the end of the molecular chain of the liquid crystal compound independently has a terminal substituent selected from a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, and a halogenated or unsubstituted chain alkenyloxy group.

[0056] Firstly, the introduction of substituted or unsubstituted thiophene rings can increase the conjugated structure of the liquid crystal compound and its birefringence. Adding this liquid crystal compound to a liquid crystal composition can enhance its birefringence while maintaining a relatively low viscosity and good low-temperature stability. Secondly, the presence of substituted or unsubstituted thiophene rings can impart a slightly curved, irregular rod-like shape to the liquid crystal compound. When added to a liquid crystal composition, this can moderately disrupt the regular arrangement of the liquid crystal molecules, resulting in a liquid crystal composition with a relatively high birefringence while also moderately reducing its clearing point, thereby lowering the temperature of subsequent heat treatment of the composition. Furthermore, while the clearing point of the liquid crystal composition is reduced, its crystallization point / freezing point does not change significantly, or even decreases modestly, thereby maintaining good low-temperature stability. Furthermore, the non-hydrogen substituents on the Ar ring at the end of the molecular chain of this liquid crystal compound are beneficial for ensuring the compound's structural stability and the good low-temperature stability of the liquid crystal composition to which it is added.

[0057] In the present application, if a substituted or unsubstituted thiophene ring is located at one end of the liquid crystal compound, then at least the Ar ring disposed at the other end of the liquid crystal compound molecular chain has the above-mentioned terminal substituent. If a substituted or unsubstituted thiophene ring is located in the middle of the liquid crystal compound molecular chain (e.g., between any two adjacent Ar rings), then at least the Ar rings disposed at both ends of the liquid crystal compound molecular chain have the above-mentioned terminal substituent.

[0058] In the present application, there is a connecting group between the two Ar rings, or between the Ar ring and the substituted or unsubstituted thiophene ring, rather than being connected to form a fused ring structure in a parallel ring form. In the embodiment of the present application, the connecting group can independently include one or more of a straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, -N=CH-. These connecting groups can ensure that the above-mentioned liquid crystal composition is easier to prepare.

[0059] Taking the example of 3 Ar rings in the above-mentioned liquid crystal compound, if the substituted or unsubstituted thiophene ring is represented by the symbol S' and the above-mentioned connecting group is represented by Z, the above-mentioned liquid crystal compound in this application can be represented as: Ar-Z-Ar-Z-Ar-Z-S', or Ar-Z-Ar-Z-S'-Z-Ar, Ar-Z-S'-Z-Ar-Z-Ar, etc.

[0060] In some embodiments of the present application, the liquid crystal compound has any one of the following general formulas: (I-A), (I-B), and (I-C):

[0061]

[0062] wherein R1 and R2 are each independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, and halogenated or unsubstituted chain alkenyloxy;

[0063] X1~X 14 Each occurrence is independently selected from a hydrogen atom (H), a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group, and at least one of X3 and X4 is a hydrogen atom. In formula (I-B), X 11 With X 12 At least one of them is a hydrogen atom;

[0064] Each occurrence of Z1, Z2, and Z3 is independently selected from one of a straight-chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-; and Z1, Z2, and Z3 are not straight-chain single bonds at the same time.

[0065] The liquid crystal compound represented by formula (I-A) contains three substituted or unsubstituted benzene rings, a thiophene ring substituted by R2 is located at one end of the compound's molecular chain, and a benzene ring substituted by R1 is located at the other end of the compound's molecular chain. From the left end to the right end of the compound represented by formula (I-A), the first substituted benzene ring and the second substituted or unsubstituted benzene ring are connected by Z1, the second and third substituted or unsubstituted benzene rings are connected by Z2, and the third substituted or unsubstituted benzene ring and the thiophene ring are connected by Z3.

[0066] The liquid crystal compound represented by formula (I-B) contains three substituted or unsubstituted benzene rings, wherein the substituted or unsubstituted thiophene ring is located in the middle of the compound molecular chain, and the benzene ring substituted by R1 and the benzene ring substituted by R2 are located at the other ends of the compound molecular chain. The equivalent structure of formula (I-B) is as follows:

[0067]

[0068] The liquid crystal compound represented by formula (I-C) contains five substituted or unsubstituted benzene rings, wherein the thiophene ring substituted by R2 is located at one end of the compound molecular chain, and the benzene ring substituted by R1 is located at the other end of the compound molecular chain. From the left end to the right end of the compound represented by formula (I-A), the first substituted benzene ring and the second substituted or unsubstituted benzene ring are directly connected by a single bond, the second and third substituted or unsubstituted benzene rings are connected by Z1, the third and fourth substituted or unsubstituted benzene rings are directly connected by a single bond, the fourth and fifth substituted or unsubstituted benzene rings are connected by Z2, and the fifth substituted or unsubstituted benzene ring and the thiophene ring are connected by Z3.

[0069] In the above formulas (I-A), (I-B), and (I-C), the non-hydrogen groups R1 and R2 located on the benzene ring or thiophene ring at the end of the liquid crystal compound molecular chain are more conducive to ensuring the structural stability of the above compounds and the good low-temperature stability of the liquid crystal composition added thereto. "In formulas (I-A), (I-B), and (I-C), at least one of X3 and X4 is a hydrogen atom; in formula (I-B), X 11 With X 12 At least one of them is a hydrogen atom", which can ensure that the above-mentioned liquid crystal compounds are easier to prepare, basically maintain the rod-shaped structure, still have liquid crystal properties, and the mixture containing them can also exhibit good liquid crystal properties. The term "liquid crystal properties" refers to the fact that a substance can have the fluidity of a liquid and the anisotropic ordered arrangement properties of a crystalline substance at a certain temperature. In addition, "the above-mentioned selection range of Z1, Z2, and Z3 can ensure that the above-mentioned liquid crystal compounds are easier to prepare; Z1, Z2, and Z3 are not linear single bonds at the same time" can ensure that the birefringence of the above-mentioned liquid crystal compounds is higher.

[0070] In the various options for Z1, Z2, and Z3 described above, -CH=CH- can be referred to as vinylene; -CF=CF- can be referred to as perfluorovinylene; -C≡C- can be referred to as an acetylenic bond; -CO-O- or -O-CO- can be referred to as an ester bond; -CH2-O- or -O-CH2- can be referred to as a methylene ether bridge bond; -CF2O- or -OCF2- can be referred to as a difluoromethylene ether bridge bond; -CH2-CH2- can be referred to as ethylene; -CF2-CF2- can be referred to as perfluoroethylene; -CF2-CH2- or -CH2-CF2- can be referred to as difluoroethylene. When Z1, Z2, or Z3 is a linear bond, it means that the structures on both sides thereof are directly connected.

[0071] In some embodiments of the present application, each occurrence of Z1, Z2, and Z3 is independently selected from a linear single bond, -CH=CH-, -C≡C-, -COO-, -OCO-, -CF2O-, and -OCF2-; and Z1, Z2, and Z3 are not all linear single bonds. In some embodiments, at least one of Z1, Z2, and Z3 is an acetylenic bond (-C≡C-).

[0072] In this application, "halogenated..." means that any one or more hydrogen atoms in a group are replaced by a halogen atom, that is, the substituent in the group is a halogen atom. For example, a halogenated straight-chain alkyl group specifically refers to a straight-chain alkyl group substituted by a halogen atom. Similarly, a halogenated straight-chain alkoxy group refers to a straight-chain alkoxy group substituted by a halogen atom; a halogenated alkenyl group refers to a alkenyl group substituted by a halogen atom; and a halogenated alkenyloxy group refers to an alkenyloxy group substituted by a halogen atom. The introduction of a halogenated group can enrich the variety of the above-mentioned compounds, obtain certain compound products with slightly different properties, and better realize applications. The halogenated group can be partially halogenated or perhalogenated. "Perhalogenated" means that all hydrogen atoms in the above-mentioned group are replaced by halogen atoms. "Partially halogenated" means that some of the hydrogen atoms in the above-mentioned group are replaced by halogen atoms. The halogen atom can be one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), with fluorine atom being more common. In some embodiments, each of the above-mentioned halogenated groups is specifically a fluorinated corresponding group.

[0073] In this application, the halogenated or unsubstituted alkyl group is linear, where "linear" specifically means that all carbon atoms constituting the alkyl group are in the same carbon chain. The liquid crystal compound containing such a halogenated or unsubstituted linear alkyl group can exhibit liquid crystal properties. Similarly, the liquid crystal compound containing a halogenated or unsubstituted linear alkoxy group can also exhibit good liquid crystal properties.

[0074] In the embodiment of the present application, the halogenated or unsubstituted linear alkyl mentioned above can be a halogenated or unsubstituted C1-C 10 Straight-chain alkyl. In some embodiments, the halogenated or unsubstituted straight-chain alkyl is a halogenated or unsubstituted C1-C9 straight-chain alkyl, a halogenated or unsubstituted C1-C6 straight-chain alkyl, a halogenated or unsubstituted C1-C4 straight-chain alkyl, etc. For example, it is a halogenated or unsubstituted methyl, a halogenated or unsubstituted ethyl, a halogenated or unsubstituted n-propyl, a halogenated or unsubstituted n-butyl, a halogenated or unsubstituted n-pentyl, a halogenated or unsubstituted n-hexyl, a halogenated or unsubstituted n-heptyl, a halogenated or unsubstituted n-octyl, etc. In some embodiments, the halogenated or unsubstituted straight-chain alkyl is a fluorinated or unsubstituted C1-C 10Straight chain alkyl. For example, the halogenated straight chain alkyl can be trifluoromethyl (-CF3), difluoroethyl (-C2F2H3), perfluoroethyl (-C2F5), perfluoropropyl (-C3F7), perfluoro-n-butyl (-C4F9), perfluoro-n-pentyl (-C5F 11 )wait.

[0075] In the present application, the halogenated or unsubstituted straight-chain alkoxy mentioned above can be regarded as the structure of the halogenated or unsubstituted straight-chain alkyl group connected to an oxygen atom (O). Therefore, the number of carbon atoms of the halogenated or unsubstituted straight-chain alkoxy group can refer to the description of the halogenated or unsubstituted straight-chain alkyl group in the previous text of the present application. In the embodiment of the present application, the halogenated or unsubstituted straight-chain alkoxy group can be a halogenated or unsubstituted C1~C 10 The straight chain alkoxy group may further be a halogenated or unsubstituted C1 to C9 straight chain alkoxy group, a halogenated or unsubstituted C1 to C8 straight chain alkoxy group, or a halogenated or unsubstituted C1 to C6 straight chain alkoxy group. In some embodiments, the halogenated or unsubstituted straight chain alkoxy group is a fluorinated or unsubstituted C1 to C 10 Straight-chain alkoxy. For example, the halogenated or unsubstituted straight-chain alkoxy group can be an unsubstituted methoxy group (—OCH 3 ), a trifluoromethoxy group (—OCF 3 ), an unsubstituted ethoxy group (—OCH 2 CH 3 ), a fluoroethoxy group, an unsubstituted propoxy group (—OCH 2 CH 2 CH 3 ), a fluoropropoxy group, an unsubstituted butoxy group (—OCH 2 CH 2 CH 2 CH 3 ), a fluorobutoxy group, and the like.

[0076] In the embodiment of the present application, the halogenated or unsubstituted chain alkenyl mentioned above can be a halogenated or unsubstituted C2 to C 10 Chain alkenyl; specifically, it can be straight chain alkenyl or branched chain alkenyl. In some embodiments, the halogenated or unsubstituted chain alkenyl is a halogenated or unsubstituted C2-C 20 Straight-chain alkenyl. The above-mentioned liquid crystal compound with the halogenated or unsubstituted straight-chain alkenyl is relatively easy to prepare, and the mixture formed by using the compound can exhibit good liquid crystal properties. In some embodiments, the halogenated or unsubstituted chain alkenyl can be a halogenated or unsubstituted C2~C9 chain alkenyl, a halogenated or unsubstituted C2~C6 chain alkenyl, etc. In some embodiments, the above-mentioned halogenated or unsubstituted chain alkenyl is a fluorinated or unsubstituted chain alkenyl. For example, the halogenated or unsubstituted chain alkenyl can be, for example, vinyl (such as CH2=CH-), difluorovinyl (CF2=CH-), perfluorovinyl (CF2=CF-), fluorinated or unsubstituted propenyl, fluorinated or unsubstituted butenyl, etc.

[0077] In the embodiments of the present application, the halogenated or unsubstituted chain alkenyloxy group mentioned above can be a straight chain alkenyloxy group or a branched chain alkenyloxy group, and the straight chain alkenyloxy group is preferred. Among them, the halogenated or unsubstituted chain alkenyloxy group can be regarded as a structure in which a halogenated or unsubstituted chain alkenyl group is connected to an oxygen atom. Therefore, the number of carbon atoms of the substituted or unsubstituted chain alkenyloxy group can refer to the description of the substituted or unsubstituted chain alkenyl group in this application. In the embodiments of the present application, the halogenated or unsubstituted chain alkenyloxy group can be a halogenated or unsubstituted C2~C 10 Alkenyloxy may further be a halogenated or unsubstituted C2 to C9 alkenyloxy, or a C2 to C6 alkenyloxy, etc. In some embodiments, the halogenated or unsubstituted chain alkenyloxy is a fluorinated or unsubstituted chain alkenyloxy. For example, the halogenated or unsubstituted alkenyloxy may be vinyloxy (such as CH2=CH-O-), difluorovinyloxy (CF2=CH-O-), perfluorovinyloxy (CF2=CF-O-), fluorinated or unsubstituted propyleneoxy, fluorinated or unsubstituted butenyloxy, etc.

[0078] In the embodiment of the present application, the unsubstituted cycloalkyl mentioned above can be specifically an unsubstituted C3 to C 10 The cycloalkyl group may further be a C3-C6 cycloalkyl group, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like.

[0079] The above groups have a suitable number of carbon atoms, which not only makes it easier to prepare the compounds represented by the above formula (I-A), formula (I-B) and formula (I-C), but also ensures that the compositions using them have a lower viscosity.

[0080] In some embodiments of the present application, X1 to X 14 Each occurrence is independently selected from one of hydrogen atom (H), halogen atom, halogenated or unsubstituted C1-C6 straight-chain alkyl, halogenated or unsubstituted C1-C6 straight-chain alkoxy, halogenated or unsubstituted C2-C6 chain alkenyl, halogenated or unsubstituted C2-C6 chain alkenyloxy, and unsubstituted C3-C6 cycloalkyl. Further, in some embodiments, X1-X 14 Each occurrence is independently selected from one of hydrogen atom (H), fluorine atom (F), fluorinated or unsubstituted C1~C6 straight-chain alkyl, fluorinated or unsubstituted C1~C6 straight-chain alkoxy, fluorinated or unsubstituted C2~C6 chain alkenyl, fluorinated or unsubstituted C2~C6 chain alkenyloxy, and unsubstituted C3~C6 cycloalkyl.

[0081] In the above-mentioned formula (Ⅰ-A), formula (Ⅰ-B) and formula (Ⅰ-C) of the present application, at least one of X3 and X4 is a hydrogen atom. That is, X3 and X4 are not the non-hydrogen groups mentioned above (such as halogen atoms, straight-chain alkyl groups, straight-chain alkoxy groups, chain alkenyl groups, chain alkenyloxy groups, cycloalkyl groups, etc.). In this case, each of the above-mentioned liquid crystal compounds can basically maintain a rod-like structure, so that it has good liquid crystal properties, and then the mixture using the above-mentioned liquid crystal compounds as monomers can exhibit good liquid crystal properties. It should be noted that the limitations on X3 and X4 here are all for X3 and X4 in the same general formula. Similar expressions below in this application should be understood in the same way.

[0082] In some embodiments of the present application, in the above-mentioned formula (I-A), formula (I-B), and formula (I-C), at least one of X3 and X4 is a hydrogen atom; at least one of X1 and X3 is a hydrogen atom, and at least one of X2 and X4 is a hydrogen atom. This ensures that the substance represented by the above-mentioned formula (I-A), formula (I-B), or formula (I-C) does not introduce too many substituents and basically maintains its rod-shaped structure, thereby enabling it to have good liquid crystal properties, and furthermore, a mixture using it as a monomer can exhibit good liquid crystal properties. Taking formula (I-A) as an example, when X4 is a hydrogen atom and X3 is a non-hydrogen group, then X1 is a hydrogen atom, and X2 can be a non-hydrogen group or a hydrogen atom; when X3 is a hydrogen atom and X4 is a non-hydrogen group, then X2 is a hydrogen atom, and X1 can be a non-hydrogen group or a hydrogen atom; when X3 and X4 are both hydrogen atoms, X1 and X2 are independently non-hydrogen groups or hydrogen atoms.

[0083] Similarly, in some embodiments of the present application, in formula (I-B), X 11 With X 12 At least one of X9 and X 11 At least one of them is a hydrogen atom; X 10 With X 12 At least one of them is a hydrogen atom. For example, when X 12 is a hydrogen atom, X 11 When it is a non-hydrogen group, X9 is a hydrogen atom, X 10 It can be a non-hydrogen group or a hydrogen atom; when X 11 is a hydrogen atom, X 12 When X is a non-hydrogen group, 10 is a hydrogen atom, X9 can be a non-hydrogen group or a hydrogen atom; when X 11 With X 12 When both are hydrogen atoms, X9, X 10 are independently non-hydrogen groups or hydrogen atoms.

[0084] In some embodiments of the present application, in formula (I-A), X4 is a hydrogen atom and Z2 is a linear single bond. In this case, formula (I-A) is specifically:

[0085]

[0086] Wherein, Z1 and ZZ3 are not linear single bonds at the same time. Further, at least one of X1 and X3 is a hydrogen atom.

[0087] When Z1 and Z3 in the substance represented by formula (I-A-1) are both -C≡C-, the synthesis route is as follows:

[0088]

[0089] The Sonogashira coupling reaction (also known as the Sonogashira-Hagihara coupling reaction) is a cross-coupling reaction of aryl or alkenyl halides with terminal alkynes in the presence of palladium or copper catalysts. The Suzuki coupling reaction (also known as the Suzuki reaction) is a cross-coupling reaction of aryl or alkenyl boronic acids or esters with halogenated aromatic compounds catalyzed by a zero-valent palladium complex.

[0090] Generally, each preparation step of the above synthetic route needs to be purified and refined. The purification and refining methods include but are not limited to one or more of chromatography, recrystallization, sublimation and adsorption.

[0091] In some other embodiments of the present application, in formula (I-A), X4 is a hydrogen atom and Z1 is a linear single bond. In this case, formula (I-A) is specifically:

[0092]

[0093] Wherein, Z2 and Z3 are not both linear single bonds. Further, at least one of X1 and X3 is a hydrogen atom.

[0094] In some embodiments, in formula (Ⅰ-A-2), Z2 and Z3 are both -C≡C-, which can be synthesized using a similar route to the above formula (Ⅰ-A-1) where Z1 and Z3 are both -C≡C-.

[0095] In some other embodiments of the present application, in formula (I-A), X3 is a hydrogen atom and Z3 is a linear single bond. In this case, formula (I-A) is specifically:

[0096]

[0097] Wherein, Z1 and Z2 are not linear single bonds at the same time. Further, at least one of X2 and X4 is a hydrogen atom.

[0098] Wherein, the equivalent structure of formula (I-A-3) is as follows:

[0099]

[0100] In some embodiments, in formula (Ⅰ-A-3), Z1 and Z2 are both -C≡C-, which can be synthesized using a similar route to the above formula (Ⅰ-A-1) where Z1 and Z3 are both -C≡C-.

[0101] In some embodiments of the present application, in formula (I-B), X4, X 12 are all hydrogen atoms, and Z1 is a straight chain single bond. In this case, the formula (I-B) is specifically:

[0102]

[0103] Wherein, Z2 and Z3 are not linear single bonds at the same time. Further, at least one of X1 and X3 is a hydrogen atom; X9 and X 11 At least one of them is a hydrogen atom.

[0104] In other embodiments of the present application, in formula (I-B), X4, X 12 are all hydrogen atoms, and Z2 is a straight chain single bond. In this case, the formula (I-B) is specifically:

[0105]

[0106] Wherein, Z1 and Z3 are not linear single bonds at the same time. Further, at least one of X1 and X3 is a hydrogen atom; X9 and X 11 At least one of them is a hydrogen atom.

[0107] In some other embodiments of the present application, in formula (I-B), X 11 , X3 is a hydrogen atom, and Z3 is a straight chain single bond. In this case, formula (I-B) is specifically:

[0108]

[0109] Wherein, Z1 and Z2 are not linear single bonds at the same time. Further, at least one of X2 and X4 is a hydrogen atom; X 10 With X 12 At least one of them is a hydrogen atom.

[0110] Among them, the equivalent structure of formula (I-B-3) is as follows:

[0111]

[0112] In some embodiments of the present application, in formula (I-C), X4 is a hydrogen atom and Z3 is a linear single bond. It is understood that Z1 and Z2 are not both linear single bonds. In this case, formula (I-C) is specifically:

[0113]

[0114] In some embodiments, in formula (I-C), when Z1 and Z2 are both -C≡C-, they can be synthesized using a similar route to the above formula (I-A-1) where Z1 and Z3 are both -C≡C-.

[0115] In some embodiments of the present application, the liquid crystal compound has the general formula shown in Formula (I-A). Compared to the structure shown in Formula (I-B), the thiophene ring in the structure shown in Formula (I-A) is located at the terminal group of the compound, and the compound having this structure has a higher birefringence. Furthermore, the liquid crystal compound has any one of the general formulas shown in the following Formulas (I-A-1), (I-A-2), and (I-A-3).

[0116] As an example, the substance represented by the above formula (I-A-1) can be selected from one or more of the following compounds:

[0117]

[0118] As an example, the substance represented by the above formula (I-A-2) can be selected from one or more of the following compounds:

[0119]

[0120] As an example, the substance represented by the above formula (I-A-3) can be selected from one or more of the following compounds:

[0121]

[0122]

[0123] As an example, the substance represented by the above formula (I-B-1) can be selected from one or more of the following compounds:

[0124]

[0125]

[0126] As an example, the substance represented by the above formula (I-B-2) can be selected from one or more of the following compounds:

[0127]

[0128] As an example, the substance represented by the above formula (I-C) can be selected from one or more of the following compounds:

[0129]

[0130] The present invention also provides a liquid crystal composition comprising a liquid crystal monomer, wherein the liquid crystal monomer comprises at least one of the liquid crystal compounds described above. For ease of presentation, the liquid crystal compound described above is referred to as the first liquid crystal compound below.

[0131] By introducing the above-mentioned first liquid crystal compound into the liquid crystal composition, the birefringence of the liquid crystal composition can be improved by means of its irregular rod-shaped conjugated molecular structure, while its viscosity and clearing point can be reduced, and its low-temperature stability, as well as its light and thermal stability can be improved. Therefore, the liquid crystal composition can be used to obtain a liquid crystal device with good performance such as faster response time and stronger low-temperature resistance.

[0132] In the embodiments of the present application, the total weight percentage of the first liquid crystal compound in the liquid crystal composition is in the range of 0.01% to 60%, for example, 0.05%, 1%, 2%, 5%, 10%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc. In some embodiments, the total weight percentage of the first liquid crystal compound in the liquid crystal composition is 1% to 50%, and can further be 1% to 30%, or 3% to 25%, etc. Adding an appropriate amount of the first liquid crystal compound helps it fully function and improve the overall performance of the liquid crystal composition.

[0133] In some embodiments of the present application, the liquid crystal composition includes one or more first liquid crystal compounds represented by Formula (I-A), Formula (I-B), or Formula (I-C). In some embodiments, the liquid crystal composition includes at least one first liquid crystal compound represented by Formula (I-A). The first liquid crystal compound represented by Formula (I-A) has a low melting point and a high birefringence. Adding the first liquid crystal compound to the liquid crystal composition can improve the low-temperature stability of the liquid crystal composition while also achieving a higher birefringence.

[0134] In some embodiments of the present application, the liquid crystal monomer in the liquid crystal composition further comprises one or more second liquid crystal compounds represented by the following formula (II-1), formula (II-2), formula (II-3), and formula (II-4):

[0135]

[0136] Among them, R a 、R b Each occurrence of R is independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, halogenated or unsubstituted chain alkenyloxy, and substituted or unsubstituted cycloalkyl; cOne selected from the group consisting of a fluorine atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and a substituted or unsubstituted cycloalkyl group;

[0137] X 1 ~X 11 Each occurrence is independently selected from one of a hydrogen atom, a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted straight-chain alkylthio group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group;

[0138] Z 1 、Z 2 Independently selected from one of a straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-; in formula (Ⅱ-4), m is 0 or 1.

[0139] The liquid crystal composition contains both the first liquid crystal compound and the second liquid crystal composition as liquid crystal monomers, which can ensure that the mixture containing them has good liquid crystal properties, and can be adjusted to obtain a liquid crystal composition that takes into account higher birefringence, lower viscosity, appropriate clearing point, lower crystallization point, wider nematic phase temperature range, high dielectric anisotropy, and higher optical, thermal and chemical stability, making the liquid crystal composition more promising in application.

[0140] In formula (II-4), when m is 0, it represents R c Directly with R a The structure shown in formula (II-4) is specifically a single benzene ring structure as shown below:

[0141]

[0142] Among them, for the description of the halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, and halogenated or unsubstituted chain alkenyloxy involved in the structural formula of the above-mentioned second liquid crystal compound, please refer to the introduction in the previous text of this application and will not be repeated here.

[0143] In the embodiment of the present application, when R a 、R b 、R cWhen the substituted cycloalkyl group is a substituted cycloalkyl group, the substituents in the substituted cycloalkyl group include one or more of a halogenated or unsubstituted linear alkyl group, a halogenated or unsubstituted linear alkoxy group, a halogenated or unsubstituted linear alkenyl group, a halogenated or unsubstituted linear alkenyloxy group, and an alkyl-substituted or unsubstituted cycloalkyl group. The introduction of various substituents can enrich the variety of the second liquid crystal compound, obtain compound products with slightly different properties, and better realize applications.

[0144] The substituted or unsubstituted cycloalkyl mentioned above can be a substituted or unsubstituted C3-C 20 Cycloalkyl. Wherein, for substituted cycloalkyl, the number of carbon atoms specifically refers to the number of carbon atoms in the unsubstituted cycloalkyl corresponding to the substituted cycloalkyl. In some embodiments, the substituted or unsubstituted cycloalkyl is a substituted or unsubstituted C3~C 15 Cycloalkyl, substituted or unsubstituted C3~C 10 Cycloalkyl, substituted or unsubstituted C3-C6 cycloalkyl, etc., for example, substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, etc. For example, the substituted cycloalkyl can be a methyl-substituted cyclopentyl, a methyl-substituted cyclohexyl, a trifluoromethyl-substituted cyclohexyl, a difluorovinyl-substituted cyclohexyl, a cyclohexyl substituted by a propyl-substituted cyclohexyl, etc.

[0145] In some embodiments of the present application, in formula (II-1), formula (II-2), and formula (II-3), R a 、R b Each occurrence is independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, and halogenated or unsubstituted chain alkenyloxy. In this case, the synthesis difficulty of the substances represented by formula (II-1), formula (II-2), and formula (II-3) is relatively low. In some embodiments of the present application, only R in formula (II-4) a 、R c The range of the selection of may include substituted or unsubstituted cycloalkyl groups. In this case, the compound of formula (II-4) having the substituted or unsubstituted cycloalkyl group is easier to synthesize.

[0146] The "halogenated or unsubstituted straight-chain alkylthio group" mentioned above can be regarded as the structure of the above-mentioned halogenated or unsubstituted straight-chain alkyl group connected to a sulfur atom (S). Therefore, the number of carbon atoms of the halogenated or unsubstituted straight-chain alkylthio group can refer to the description of the halogenated or unsubstituted straight-chain alkyl group in the previous text of this application. In the embodiment of this application, the halogenated or unsubstituted straight-chain alkylthio group can be a halogenated or unsubstituted C1~C 10The straight chain alkylthio group may further be a halogenated or unsubstituted C1 to C8 straight chain alkylthio group, or a halogenated or unsubstituted C1 to C6 straight chain alkylthio group. In some embodiments, the halogenated or unsubstituted straight chain alkylthio group is a fluorinated or unsubstituted C1 to C 10 Straight-chain alkylthio. For example, the halogenated or unsubstituted straight-chain alkylthio can be unsubstituted methylthio (-SCH3), trifluoromethylthio (-SCF3), unsubstituted ethylthio (-SCH2CH3), fluoroethylthio, unsubstituted propylthio (-SCH2CH2CH3), fluoropropylthio, unsubstituted butylthio (-SCH2CH2CH2CH3), fluorobutylthio, etc.

[0147] In some embodiments, X 1 ~X 11 Each occurrence is independently selected from one of the group consisting of a hydrogen atom (H), a fluorine atom (F), a chlorine atom (Cl), a fluorinated or unsubstituted C1-C6 straight-chain alkyl group, a fluorinated or unsubstituted C1-C6 straight-chain alkoxy group, a fluorinated or unsubstituted C1-C6 straight-chain alkylthio group, a fluorinated or unsubstituted C2-C6 chain alkenyl group, a fluorinated or unsubstituted C2-C6 chain alkenyloxy group, and an unsubstituted C3-C6 cycloalkyl group.

[0148] Similar to the above, in the embodiment of the present application, in formula (II-1), X 1 With X 3 At least one of them is a hydrogen atom, X 4 With X 6 At least one of them is a hydrogen atom, X 7 With X 9 At least one of them is a hydrogen atom, X 10 With X 12 At least one of them is a hydrogen atom. In formula (II-2), X 1 With X 3 At least one of them is a hydrogen atom, X 4 With X 6 At least one of them is a hydrogen atom, X 7 With X 9 At least one of them is a hydrogen atom. In formula (II-3) and formula (II-4), X 4 With X 6 At least one of them is a hydrogen atom. This helps ensure that the substance represented by formula (II-1), formula (II-2), formula (II-3) or formula (II-4) basically maintains a rod-like structure, and the mixture of them with the above-mentioned first liquid crystal compound can exhibit good liquid crystal properties.

[0149] In some embodiments, in formula (II-1), X 5 With X 7 At least one of them is a hydrogen atom, X 8 With X10 At least one of them is a hydrogen atom; in formula (II-2), X 5 With X 7 In this case, the difficulty of synthesizing the substance represented by formula (II) and the substance represented by formula (III) is greatly reduced.

[0150] In some embodiments, in formula (II-1), X 1 are all H atoms, X 7 is a hydrogen atom, X 10 is a hydrogen atom. In formula (II-2), X 1 are all H atoms, X 7 is a hydrogen atom, X 4 With X 6 At least one of them is a hydrogen atom.

[0151] As an example, the substance represented by the above formula (II-1) in this application can be specifically selected from one or more of the following compounds:

[0152]

[0153]

[0154] As an example, the substance represented by the above formula (II-2) can be specifically selected from one or more of the following compounds:

[0155]

[0156]

[0157]

[0158] As an example, the substance represented by the above formula (II-3) can be specifically selected from one or more of the following compounds:

[0159]

[0160]

[0161] As an example, the substance represented by the above formula (II-4) can be specifically selected from one or more of the following compounds:

[0162]

[0163]

[0164] In some embodiments of the present application, the liquid crystal composition includes multiple second liquid crystal compounds represented by formula (II-2), formula (II-3) and formula (II-4). In this case, the viscosity of the liquid crystal composition at room temperature is relatively low.

[0165] In embodiments of the present application, the total weight percentage of the second liquid crystal compound in the liquid crystal composition is in the range of 0.5% to 78%, for example, 0.8%, 1%, 2%, 5%, 10%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 68%, 70%, 72%, 75%, 76%, or 77%. In some embodiments, the total weight percentage of the second liquid crystal compound in the liquid crystal composition is 40% to 78%, or further, 50% to 76%. Adding an appropriate amount of the second liquid crystal compound in combination with the first liquid crystal compound can ensure that the liquid crystal composition containing them has excellent liquid crystal properties, strong fluidity, a high birefringence, resistance to crystallization at low temperatures, a low clearing point, and high optical, thermal, and chemical stability. The aforementioned properties of the composition can also be slightly varied to meet the application requirements of different scenarios.

[0166] In some embodiments of the present application, in the liquid crystal composition, the weight percentage of the second liquid crystal compound is greater than the weight percentage of the first liquid crystal compound. This facilitates the liquid crystal composition to have a higher birefringence and low-temperature stability. In some embodiments, in the liquid crystal composition, the total weight percentage of the first liquid crystal compound is 1% to 30%, and further can be 3% to 25%, while the total weight percentage of the second liquid crystal compound is 40% to 78%.

[0167] In some embodiments of the present application, the liquid crystal composition may further include additives, including one or more of a UV absorber, a UV stabilizer, an antioxidant, and a voltage stabilizer. The presence of the additives may help improve one or more of the UV resistance, high-temperature stability, and chemical oxidation resistance of the liquid crystal composition. The additives may be added as needed.

[0168] In embodiments of the present application, the weight percentage of the additive in the liquid crystal composition is in the range of 0.01%-10%, for example, 0.02%, 0.05%, 0.1%, 0.5%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%. In some embodiments, the weight percentage of the additive in the liquid crystal composition is in the range of 0.05%-5%, or 0.1%-3%. Incorporating an appropriate amount of the additive into the liquid crystal composition can effectively improve the light resistance, heat resistance, and chemical oxidation resistance of the liquid crystal composition while not significantly affecting the birefringence and viscosity of the composition.

[0169] Illustratively, the above-mentioned additives may have one or more of the following structures:

[0170]

[0171]

[0172] Where n represents an integer from 1 to 20, R 13 、R 14 、R 15 、R 16 Independently selected from linear alkyl or linear alkoxy groups having 1 to 10 carbon atoms.

[0173] In an embodiment of the present application, the birefringence Δn of the liquid crystal composition may be greater than 0.34, for example, in the range of 0.35-0.45. A higher birefringence is more conducive to the application of the liquid crystal composition in the fields of optical communications and wireless communications. For example, the Δn may be 0.34, 0.350, 0.355, 0.358, 0.360, 0.370, 0.380, 0.390, 0.40, 0.41, 0.42, 0.43, etc.

[0174] In an embodiment of the present application, the clearing point of the above-mentioned liquid crystal composition is in the range of 110-140°C. The term "clearing point" (English: clearing point) refers to the critical temperature when the liquid crystal substance transforms into a liquid state, that is, the highest temperature at which the liquid crystal state can exist. The clearing point of the liquid crystal composition is in a suitable range, which can not only ensure that the temperature of the subsequent heating process of the liquid crystal composition is not too high, but also ensure that the liquid crystal composition can stably maintain a liquid crystal state at a relatively high temperature and does not cause the liquid crystal device to fail. Specifically, the clearing point of the liquid crystal composition can be 115°C, 120°C, 122°C, 125°C, 128°C, 130°C, 133°C, 135°C, or 138°C, etc. In some embodiments, the clearing point is in the range of 120-135°C.

[0175] In the embodiment of the present application, the liquid crystal composition does not crystallize after being stored at -30°C for 20 days. This indicates that the liquid crystal composition has a low crystallization point or freezing point and good low-temperature stability, and thus a liquid crystal device made with the liquid crystal composition can be used in a low-temperature environment.

[0176] In the embodiment of the present application, the viscosity of the liquid crystal composition at 25° C. is below 750 mPa, for example, in the range of 450-750 mPa·s. This indicates that the liquid crystal composition has good fluidity at room temperature and is easy to apply.

[0177] The embodiments of the present application also provide the application of the above-mentioned liquid crystal composition in a liquid crystal device. Among them, the liquid crystal composition is mainly used in the liquid crystal layer of the liquid crystal device. It can be understood that the liquid crystal device includes a liquid crystal layer. Generally, the liquid crystal device includes a first substrate with a first electrode layer, a second substrate with a second electrode layer, and a liquid crystal layer arranged between the first substrate and the second substrate. The liquid crystal layer can be made using the liquid crystal composition of the embodiments of the present application. Because the liquid crystal molecules in the liquid crystal layer can rotate under the action of an electric field of a certain intensity, their refractive index changes, and the optical signal can be phase modulated. Generally, this liquid crystal device can be called a "liquid crystal-based electro-optical adjustment device."

[0178] In the embodiments of the present application, the liquid crystal device can be applied to fields such as display and communication, for example, specifically in display imaging (such as in-vehicle displays, holographic displays, flat panel displays, intelligent light displays, laser projection, etc.), light field modulation, optical communication, and wireless communication. Specifically, the liquid crystal device can be used in wavelength selective switches, microwave scanning antennas, liquid crystal antennas, liquid crystal optical waveguides, dynamic focusing lenses (such as dynamic focusing glasses), liquid crystal gratings, laser radars, beam trackers, projectors, flat panel displays, holographic displays, optical communication equipment, wireless communication equipment, etc., as one or more components thereof.

[0179] Exemplarily, the flat panel display may be a TFT-LCD (Thin Film Transistor-Liquid Crystal Display), which may be used in smartphones, tablet computers, or televisions. Exemplarily, a TFT-LCD display generally includes a TFT array substrate, a color filter (CF) substrate, and a liquid crystal layer sandwiched between the two. Among them, the TFT substrate is mainly responsible for the transmission of electrical signals. The CF substrate mainly provides the colors required for the display. Exemplarily, the holographic display may be an AR HUD (Augmented Reality-head up display) used in vehicle displays. In addition, the holographic display may be a display using holographic polymer dispersed liquid crystal (HPDLC); the grating may be a grating using HPDLC. Optical communication equipment and lidar may use wavelength selective switches.

[0180] In some embodiments of the present application, the liquid crystal device is specifically used in a wavelength selective switch (WSS). The liquid crystal device in this case can be Figure 1 The LCoS device shown in the preceding text of this application Figure 1 WSS modulates the phase of the optical signal through the LCoS device, thereby changing the transmission direction of the optical signal.

[0181] See also Figure 2 , Figure 2 The figure is a schematic diagram of the structure of a wavelength selective switch (WSS). In addition to the liquid crystal device 100 described above, the wavelength selective switch 200 may also include at least one input port 201 and at least one output port 202. An optical signal may be input from at least one of the multiple input ports 201, modulated by the liquid crystal device 100, and output from at least one of the multiple output ports 202, thereby changing the transmission direction of the optical signal, such as completing the exchange, upload, or download of the optical signal. The number of input ports 201 and output ports 202 may be equal or unequal, and this is not limited in this application. The input ports 201 and output ports 202 may be composed of optical fibers, and the input / output ports may form an input / output optical fiber array.

[0182] It should be understood that Figure 2 The WSS structure diagram shown is for illustrative purposes only. The WSS may also include optical path altering devices known in the art, such as gratings, lenses, reflectors, and collimators, which are not limited in this application. For example, in some embodiments, a grating may be provided between the input port 201 and the liquid crystal device 100. The grating can be used to spatially demultiplex optical signals of different wavelengths. The lens can be used to focus or collimate light. The reflector is used to reflect light.

[0183] The liquid crystal device 100 uses the above-mentioned liquid crystal composition with high birefringence and good low-temperature stability of the embodiment of the present application, so that the WSS including the liquid crystal device 100 can support a larger phase modulation amount, higher resolution, faster response time, and stronger low-temperature resistance, and has outstanding market competitiveness.

[0184] Similarly, dynamic focusing glasses using the liquid crystal devices of the embodiments of the present application can achieve greater zoom capabilities; gratings (such as holographic gratings) using the liquid crystal devices of the embodiments of the present application can have a wider field of view; holographic displays and projectors using the liquid crystal devices of the embodiments of the present application can have a greater depth of field; and TFT-LCD displays using the liquid crystal compositions of the embodiments of the present application can have higher resolution and shorter response times. Furthermore, these devices have strong low-temperature resistance.

[0185] The present application also provides an apparatus comprising the aforementioned liquid crystal device according to the present application. The apparatus may be one or more of a wavelength selective switch, a microwave scanning antenna, a liquid crystal antenna, a liquid crystal optical waveguide, a dynamic focusing lens, a liquid crystal grating, a lidar, a beam tracker, a projector, an optical projection system, a flat-panel display, a holographic display, optical communication equipment, or wireless communication equipment. The apparatus utilizing the liquid crystal device according to the present application exhibits excellent performance and stable operation.

[0186] The technical solution of the present application is further described below with reference to a number of embodiments.

[0187] Before introducing the specific embodiments of the present application, the group structures and corresponding codes involved in the present application are first introduced, as shown in Table 1 below.

[0188] Table 1

[0189]

[0190] Additive UV-P: Its Chinese name is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0191] Additive UV-770: Its Chinese name is bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0192] The testing methods for the various physicochemical parameters mentioned in this application are as follows.

[0193] The clearing point (Cp) of the liquid crystal composition can be determined from the DSC curve obtained by testing the liquid crystal composition using a differential scanning calorimetry (DSC) instrument. The DSC test is performed at a heating rate of 5° C. / min.

[0194] The Δn of a liquid crystal composition can be determined using known testing methods. For example, by mixing each liquid crystal composition provided herein with a standard liquid crystal (mother crystal) of known birefringence at a specific mass ratio, and measuring the birefringence of the resulting mixture at room temperature using an Abbe refractometer, the birefringence Δn of the added liquid crystal composition at 25°C and 589 nm can be calculated.

[0195] The specific formula of the standard liquid crystal used in this application is as follows:

[0196]

[0197] In addition, the dielectric anisotropy of the liquid crystal composition can be measured by the dielectric constant Δε, which is measured at 25°C and 1 kHz. Δε = ε || -ε ⊥ .

[0198] The viscosity of the liquid crystal composition at room temperature can be expressed as the rotational viscosity γ1, and the test temperature is 25°C.

[0199] Preparation Example 1

[0200] The synthesis route of the first liquid crystal compound 5PTVVTS3 is as follows:

[0201]

[0202] Among them, the nuclear magnetic resonance hydrogen spectrum test results of compound 5PTTVVVTS3 are: 1 H NMR(400M, CDCl3)δ: δ7.59-7.41(m,5H),7.30-7.16(m,6H),6.74(d,1H),2.84(t,2H),2.68(t,2H),2.61(s,3H),2.33(s,3H),1.80 -1.60(m,4H),1.43 -1.35(m,4H),1.06-1.03(t,3H),0.98-0.94(t,3H).ppm.

[0203] The C NMR test results of compound 5PTVVTS3 are as follows: 13 C NMR (100M, CDCl3) δ148.10,143.48,141.49,141.14,139.99,135.48,133 .22,131.97,131.56,131.49,130.22,129.74,128.78,128.56,126.47,1 24.39,122.15,122.09,120.72,120.69,94.08,92.41,87.62,83.33,35. 95,32.32,31.51,31.05,24.88,22.61,20.90,20.43,14.11,13.70.ppm.

[0204] Application Example 1

[0205] A liquid crystal composition includes 100 parts by weight of a liquid crystal monomer and 0.6 parts by weight of an additive UV-P, wherein the composition of the liquid crystal monomer is shown in Table 2. Performance test results of the liquid crystal composition are also summarized in Table 2.

[0206] Table 2

[0207]

[0208]

[0209] Application Example 2

[0210] A liquid crystal composition includes 100 parts by weight of a liquid crystal monomer and 1 part by weight of an additive UV-P, wherein the specific composition and performance test results of the liquid crystal composition are shown in Table 3 below.

[0211] Table 3

[0212]

[0213]

[0214] Comparative Example 1

[0215] A liquid crystal composition, the component composition and performance test results of which are shown in Table 4 below.

[0216] Table 4

[0217]

[0218] As can be seen from Table 4, although the isothiocyanate-based liquid crystal composition provided in Comparative Example 1 has a high birefringence, its viscosity and clearing point at room temperature are higher than those of the liquid crystal composition of Application Example 1 of this application. Furthermore, the crystallization point of the liquid crystal composition of Comparative Example 1 is too high, and its low-temperature stability is poor. After being placed in a low-temperature environment at -20°C for 500 hours, crystallization occurred, indicating that the liquid crystal composition of Comparative Example 1 has poor low-temperature resistance.

[0219] Comparative Example 2

[0220] A liquid crystal composition, the component composition and performance test results of which are shown in Table 5 below.

[0221] Table 5

[0222]

[0223]

[0224] Among them, the difference between 5PTVVTP3 in Table 5 and the first liquid crystal compound 5PTVVTS3 of the present application is that the end of the molecular structure is a substituted benzene ring instead of a thiophene ring with the same substituent; the difference between 4PTP(1)VTP3 and 4PTP(1)VTS3 of the present application is that the end of the molecular structure is a substituted benzene ring instead of a thiophene ring with the same substituent; the difference between 3PTGGTP4 and 3PTGGTS4 is that the end of the molecular structure is a substituted benzene ring instead of a thiophene ring with the same substituent.

[0225] As can be seen from Table 5, compared to Application Example 1, the liquid crystal composition of Comparative Example 2 does not contain the first liquid crystal compound containing thiophene provided in the examples of this application. While the birefringence of the two liquid crystal compositions is similar, the liquid crystal composition of Comparative Example 2 exhibits a higher clearing point and a higher room temperature viscosity. Furthermore, after being stored at -30°C for a period of time, the liquid crystal composition of Comparative Example 2 exhibits crystallization and exhibits poor low-temperature stability. These results indicate that the addition of the first liquid crystal compound provided in the examples of this application to the liquid crystal composition can help lower the clearing point and viscosity, while maintaining a high birefringence, and improve low-temperature stability.

[0226] The liquid crystal composition of Example 1 is taken as an example to test its UV resistance and high temperature stability, and the results are compared with those of Comparative Example 1.

[0227] High-temperature stability testing: Each liquid crystal composition was poured into a liquid crystal cell via capillary canning, sealed with sealing adhesive, and cured under 365nm UV light. The resulting liquid crystal cell samples were then tested for voltage holding ratio (VHR0). The liquid crystal cell samples were then placed in a 100°C oven for varying periods of time. The VHR of the liquid crystal cell samples was measured, and the change in voltage holding ratio (i.e., ΔVHR, which is equal to VHR0 - VHR) was calculated.

[0228] UV resistance test: Each liquid crystal composition was poured into a liquid crystal cell by capillary crystallization and sealed with sealing glue. The obtained liquid crystal cell sample was placed in a UV test chamber to test its UV resistance under 365nm UV lamp at 50mW / cm 2 The voltage holding ratio change (△VHR) after irradiation with an intensity of 10J.

[0229] The voltage holding ratios mentioned above were all tested using an ALCT-IV1 liquid crystal comprehensive parameter tester under the following test conditions: temperature 25°C, voltage 5V, and power-on frequency 60Hz.

[0230] Among them, the evaluation criteria for high temperature stability are as follows:

[0231] High temperature stability excellent good Poor △VHR ＜5.0％ 5.0-10.0％ ＞10.0％ VHR ＞98.0％ ＞90.0％ ＜85.0％

[0232] Among them, the evaluation criteria for UV resistance are as follows:

[0233] UV resistance excellent good Poor △VHR ＜3.0％ 3.0-5.0％ ＞5.0％ VHR ＞98.0％ ＞90.0％ ＜85.0％

[0234] Tables 6 and 7 below summarize the test results of the high temperature stability and UV resistance of the liquid crystal compositions of Application Example 1 and Comparative Example 1, respectively.

[0235] Table 6 High temperature stability test results

[0236]

[0237] Table 7 UV resistance test results

[0238]

[0239]

[0240] It can be seen from Tables 6 and 7 that under the same high-temperature aging or ultraviolet aging conditions, the light / thermal stability of the isothiocyanate-based liquid crystal composition of Comparative Example 1 is poor; while the liquid crystal composition provided in the present application can have better high-temperature stability and ultraviolet stability while maintaining a relatively high birefringence.

[0241] The foregoing merely represents exemplary embodiments of the present application, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0242] It should be noted that the words "first", "second", etc. used in this application are used to distinguish different objects, rather than to describe a specific order. The words "set", "connect", and "install" in this application should be understood in a broad sense. For example, they can be directly set, connected, or installed, or they can be indirectly set, connected, or installed through an intermediate medium. The directional terms mentioned in this application, such as "up", "down", "front", "back", "left", "right", "inside", "outside", "front", "back", "bottom", "top", etc., are only for better and clearer explanation and understanding of this application, and do not indicate or imply that the referred components must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on this application.

[0243] In the description of this application, unless otherwise specified, the meaning of "multiple (kinds)" refers to greater than or equal to two (kinds). "At least one (kind)" refers to one (kind) or more (kinds). "At least one of the following (kinds)" or similar expressions refers to any combination of these items, including any combination of single (individual) or plural (individual) items. For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple, respectively.

[0244] In addition, the numerical range indicated by "-" in this application refers to the range including the values ​​before and after the "-" as the minimum and maximum values, respectively. In this application, expressions about parameter ranges, such as "greater than or equal to (≥)", "less than or equal to (≤)", "above...", and "below...", all include the number itself.

Claims

1. A liquid crystal compound, characterized in that The liquid crystal compound includes at least three Ar rings and one substituted or unsubstituted thiophene ring arranged in a linear manner, and a connecting group connecting two of the Ar rings or between the Ar ring and the substituted or unsubstituted thiophene ring, wherein the Ar ring represents a substituted or unsubstituted benzene ring; and the Ar ring arranged at the end of the molecular chain of the liquid crystal compound independently has a substituent selected from a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, and a halogenated or unsubstituted chain alkenyloxy group.

2. The liquid crystal compound according to claim 1, wherein The connecting groups independently include one of a straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-.

3. The liquid crystal compound according to claim 1 or 2, wherein The liquid crystal compound has any one of the following general formulas: wherein R1 and R2 are each independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, and halogenated or unsubstituted chain alkenyloxy; X1~X 14 Each occurrence is independently selected from a hydrogen atom, a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group, and at least one of X3 and X4 is a hydrogen atom. In formula (I-B), X 11 With X 12 At least one of them is a hydrogen atom; Each occurrence of Z1, Z2, and Z3 is independently selected from one of a straight-chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, and -N=CH-; and Z1, Z2, and Z3 are not straight-chain single bonds at the same time.

4. The liquid crystal compound according to claim 3, wherein The halogenated or unsubstituted linear alkyl group is a fluorinated or unsubstituted C1-C 10 Straight-chain alkyl; the halogenated or unsubstituted straight-chain alkoxy is a fluorinated or unsubstituted C1~C 10 Straight chain alkoxy; the halogenated or unsubstituted chain alkenyl is a fluorinated or unsubstituted C2~C 10 Chain alkenyl; the halogenated or unsubstituted chain alkenyloxy is a fluorinated or unsubstituted C2~C 10 Chain alkenyloxy; the unsubstituted cycloalkyl is an unsubstituted C3~C 10 Cycloalkyl.

5. The liquid crystal compound according to claim 3 or 4, wherein In the formula (I-A), formula (I-B), and formula (I-C), at least one of X1 and X3 is a hydrogen atom, and at least one of X2 and X4 is a hydrogen atom; in the formula (I-B), X9 and X 11 At least one of them is a hydrogen atom; X 10 With X 12 At least one of them is a hydrogen atom.

6. The liquid crystal compound according to any one of claims 3 to 5, wherein In formula (I-A), X4 is a hydrogen atom, and Z1 or Z2 is a linear single bond; or, X3 is a hydrogen atom, and Z3 is a linear single bond.

7. The liquid crystal compound according to any one of claims 3 to 5, wherein In formula (I-B), X4, X 12 are all hydrogen atoms, Z1 or Z2 is a straight chain single bond; or, X 11 , X3 is a hydrogen atom, and Z3 is a linear single bond.

8. The liquid crystal compound according to any one of claims 3 to 5, wherein In formula (I-C), X4 is a hydrogen atom, and Z3 is a linear single bond.

9. A liquid crystal composition, characterized in that The liquid crystal composition comprises at least one liquid crystal compound according to any one of claims 1 to 8.

10. The liquid crystal composition according to claim 9, wherein In the liquid crystal composition, the total mass percentage of the liquid crystal compound is in the range of 0.01%-60%.

11. The liquid crystal composition according to claim 9 or 10, wherein The liquid crystal composition further comprises one or more second liquid crystal compounds represented by the following formula (II-1), formula (II-2), formula (II-3), and formula (II-4): Among them, R a 、R b Each occurrence of R is independently selected from one of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, halogenated or unsubstituted chain alkenyloxy, and substituted or unsubstituted cycloalkyl; c One selected from the group consisting of a fluorine atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and a substituted or unsubstituted cycloalkyl group; X 1 ~X 11 Each occurrence is independently selected from one of a hydrogen atom, a halogen atom, a halogenated or unsubstituted straight-chain alkyl group, a halogenated or unsubstituted straight-chain alkoxy group, a halogenated or unsubstituted straight-chain alkylthio group, a halogenated or unsubstituted chain alkenyl group, a halogenated or unsubstituted chain alkenyloxy group, and an unsubstituted cycloalkyl group; Z 1 、Z 2 Independently selected from one of straight chain single bond, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-CH2-, -CF2-CF2-, -CF2-CH2-, -CH2-CF2-, -N=N-, -CH=N-, -N=CH-; in formula (Ⅱ-4), m is 0 or 1.

12. The liquid crystal composition according to claim 11, wherein In the formula (II-1), formula (II-2), formula (II-3), and formula (II-4), X 4 With X 6 At least one of them is a hydrogen atom; in the formula (II-1) and formula (II-2), X 1 With X 3 At least one of them is a hydrogen atom, X 7 With X 9 At least one of them is a hydrogen atom; in the formula (II-1), X 10 With X 12 At least one of them is a hydrogen atom.

13. The liquid crystal composition according to claim 11 or 12, wherein The R a 、R b In the substituted cycloalkyl group, the substituents include one or more of halogenated or unsubstituted straight-chain alkyl, halogenated or unsubstituted straight-chain alkoxy, halogenated or unsubstituted chain alkenyl, halogenated or unsubstituted chain alkenyloxy, and alkyl-substituted or unsubstituted cycloalkyl.

14. The liquid crystal composition according to any one of claims 11 to 13, wherein: In the liquid crystal composition, the mass percentage of the second liquid crystal compound is in the range of 0.5%-78%.

15. The liquid crystal composition according to any one of claims 11 to 14, wherein In the liquid crystal composition, the mass percentage of the second liquid crystal compound is greater than the mass percentage of the liquid crystal compound.

16. The liquid crystal composition according to claim 15, wherein In the liquid crystal composition, the total mass percentage of the liquid crystal compound is 1%-30%, and the total mass percentage of the second liquid crystal compound is 40%-78%.

17. The liquid crystal composition according to any one of claims 1 to 16, wherein: The liquid crystal composition further includes additives, which include one or more of an ultraviolet absorber, an ultraviolet stabilizer, an antioxidant, and a voltage stabilizer.

18. The liquid crystal composition according to claim 17, wherein The mass percentage of the additive in the liquid crystal composition is in the range of 0.01%-10%.

19. The liquid crystal composition according to any one of claims 1 to 18, wherein The liquid crystal composition has a birefringence of greater than 0.34, a clearing point in the range of 110-140° C., a crystallization point below -30° C., and a viscosity at 25° C. in the range of 450-750 mPa·s.

20. Use of the liquid crystal compound according to any one of claims 1 to 8 or the liquid crystal composition according to any one of claims 9 to 19 in a liquid crystal device.

21. A liquid crystal device, characterized in that: The liquid crystal device comprises a liquid crystal layer, and the liquid crystal layer comprises the liquid crystal composition according to any one of claims 9 to 19, or the liquid crystal compound according to any one of claims 1 to 8.

22. The liquid crystal device according to claim 21, wherein The liquid crystal device includes a silicon-based backplane, a cover plate with a transparent electrode layer, and the liquid crystal layer arranged between the silicon-based backplane and the cover plate with the transparent electrode layer.

23. Application of the liquid crystal device according to claim 21 or 22 in wavelength selective switches, microwave scanning antennas, liquid crystal antennas, liquid crystal waveguides, dynamic focusing lenses, liquid crystal gratings, laser radars, beam tracking, projection, flat panel displays, holographic displays, optical communications, and wireless communications.

24. A device, characterized in that The device comprises the liquid crystal device according to claim 21 or 22.

25. The device according to claim 24, wherein The device includes one or more of a wavelength selective switch, a microwave scanning antenna, a liquid crystal antenna, a liquid crystal optical waveguide, a dynamic focusing lens, a liquid crystal grating, a laser radar, a beam tracker, a projector, a flat panel display, a holographic display, an optical communication device, and a wireless communication device.

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