Liquid crystal composition and liquid crystal display device

Abstract

The present invention provides a liquid crystal composition and a liquid crystal display device. The liquid crystal composition comprises at least one compound of general formula I and at least one compound selected from general formula II-1 and / or general formula II-2. The liquid crystal composition provided by the present invention has appropriate optical anisotropy, appropriate clearing point, low rotational viscosity, high K ave Values ​​and higher ε ⊥ / △ε ratio, and has high transmittance and contrast, and also has excellent low-temperature storage performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid crystal materials, and specifically relates to a liquid crystal composition and a liquid crystal display device, and in particular to a liquid crystal composition and a liquid crystal display device with positive dielectric anisotropy. Background Art

[0002] Liquid crystal materials are mixtures of organic rod-shaped small molecular compounds that have both the fluidity of liquid and the anisotropy of crystal at a certain temperature. Liquid crystal display devices work by utilizing the optical anisotropy and dielectric anisotropy of liquid crystal materials themselves, and have been widely used. Liquid crystal display elements are divided into the following types based on the operation mode of liquid crystal molecules: PC (phase change), TN (twist nematic), STN (super twisted nematic), DS (dynamic scattering), FLC (ferroelectric liquid crystal, FLC), GH (guest-host), ECB (electrically controlled birefringence), OCB (optically compensated bend), IPS (in-plane switching), VA (vertical alignment), FFS (fringe field switching), FPA (field-induced photo-reactive alignment), etc.

[0003] In the early 1970s, experimental research had been conducted on the basic electro-optical properties of uniformly arranged and twistedly arranged nematic liquid crystal IPS mode. Its characteristic is that a pair of electrodes are made on the same substrate, while there is no electrode on the other substrate. The arrangement of liquid crystal molecules is controlled by applying a lateral electric field between the pair of electrodes. Therefore, this mode can also be called a lateral field mode. In the IPS mode, the nematic liquid crystal molecules are arranged uniformly and parallel between the two substrates, and the two polarizers are placed orthogonally. When no electric field is applied to the IPS mode, the incident light is blocked by the two orthogonal polarizers and is in a dark state. When an electric field is applied, the liquid crystal molecules rotate and cause a delay, so light leaks out from the two orthogonal polarizers. The advantages of panels using the IPS mode are a large viewing angle and accurate color reproduction, but the disadvantages are severe light leakage and a slow response speed.

[0004] With the widespread application of TFT LCD, the requirements for its performance are also constantly increasing. High display image quality requires faster response speed, lower energy consumption, and higher low-temperature reliability. In addition, higher contrast and transmittance are required, especially for IPS liquid crystal display mode. This means that liquid crystal materials need to have higher contrast and transmittance, higher elastic constant, higher dielectric constant and low-temperature reliability, and the improvement of these performances requires the improvement of liquid crystal materials.

[0005] According to the transmittance formula of IPS mode, T∝|Δε| / ε ⊥ (T represents transmittance, “∝” represents the “inverse proportional” relationship, ε ⊥ Indicates the dielectric constant perpendicular to the molecular axis). To increase the transmittance of liquid crystal, we can try to reduce the Δε of the liquid crystal medium, but generally the adjustment range of the driving voltage of the same product is limited. In addition, the liquid crystal molecules will tilt toward the Z axis under the action of the vertical component of the fringe electric field, causing their optical anisotropy to change. According to the formula (where χ is the angle between the optical axis of the liquid crystal layer and the optical axis of the polarizer, Δn is the optical anisotropy, d is the cell spacing, and λ is the wavelength) It can be seen that the effective Δn*d will affect T. If the transmittance of the positive liquid crystal is to be improved, increasing Δn*d can also be considered, but the delay design of each product is fixed.

[0006] On the other hand, based on the traditional IPS-LCD light leakage performance test, it was found that the main causes of light leakage problems in liquid crystal display devices are: light scattering (LC scattering), rubbing uniformity, color filter film leakage (CF / TFT scattering) and polarization ability. Among them, light scattering accounts for 63% of the factors affecting light leakage performance.

[0007] According to the following relationship:

[0008] Where, d represents the spacing of the liquid crystal cell, n e is the extraordinary refractive index, n o represents the ordinary refractive index.

[0009] To improve the light scattering of liquid crystal materials, it is necessary to increase the average elastic constant K ave (Among them, K ave =(K 11 +K 22 +K 33 ) / 3) to improve light scattering and increase K ave In this case, light leakage of the liquid crystal material can be reduced.

[0010] In addition, the relationship between contrast (CR) and brightness (L) is as follows:

[0011] CR=L 255 / L 0 ×100%,

[0012] Among them, L 255 is the on-state brightness, L 0 is the off-state brightness. It can be seen that the one that significantly affects CR should be L 0 In the off state, L 0 It has nothing to do with the dielectric properties of liquid crystal molecules, but is related to the LC Scattering of the liquid crystal material itself; the smaller the LC Scattering, the higher the L 0 The smaller it is, the higher the CR will be.

[0013] In view of the above situation, the common methods for improving contrast and transmittance can be considered from the following two aspects: (1) keeping the dielectric anisotropy Δε of the liquid crystal composition unchanged by increasing ε ⊥ It can effectively improve the transmittance; (2) increase the average elastic constant K of the liquid crystal composition ave The value of ε can make the liquid crystal molecules more orderly and leak less light, thereby improving the transmittance. ⊥ / △ε ratio is small, K ave The value is small, resulting in insufficient transmittance, slow response, poor low-temperature storage performance, etc. Therefore, how to provide a liquid crystal composition that can solve the above problems is still a technical problem to be solved in the art. Summary of the invention

[0014] In view of the shortcomings of the prior art, the present invention aims to provide a liquid crystal composition and a liquid crystal display device. In the present invention, by designing the specific composition and structure of the compound in the liquid crystal composition, the provided liquid crystal composition has a high K ave Values ​​and higher ε ⊥ / △ε ratio, the resulting liquid crystal composition has high transmittance and contrast, and also has excellent low-temperature storage performance.

[0015] To achieve this object, the present invention adopts the following technical solutions:

[0016] In a first aspect, the present invention provides a liquid crystal composition, comprising at least one compound of formula I and at least one compound selected from formula II-1 and / or formula II-2:

[0017]

[0018] Among them, R1 represents -H, a halogenated or unhalogenated straight-chain alkyl group having 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, a halogenated or unhalogenated branched-chain alkyl group having 3 to 12 (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, a halogenated or unhalogenated alkoxy group having 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, a halogenated or unhalogenated alkenyl group having 2 to 12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, a halogenated or unhalogenated alkenyloxy group having 2 to 12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms,

[0019] R 21 and R 32 each independently represents an alkyl group having 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, an alkoxy group having 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, an alkenyl group having 2-12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, or an alkenyloxy group having 2-12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms;

[0020] R 22 represents a halogen atom, a haloalkyl group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkoxy group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkenyl group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms, or a haloalkenyloxy group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms;

[0021] R 31 represents -H, an alkyl group having 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, or an alkoxy group having 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms;

[0022] ring express

[0023] ring express in and One or at least two of the 2 - may be replaced by -O-, and the single bonds in one or at least two rings may be replaced by double bonds, wherein the and One or at least two of the -H in the above-mentioned may be independently replaced by -F, -Cl, -CN, -CH 3 or -OCH 3 Replacement, -CH= in one or at least two rings can be replaced by -N= independently;

[0024] ring ring ring and ring Each independently expresses Said One or at least two of the 2 - may be replaced by -O-, a single bond in one or at least two rings may be replaced by a double bond, and at least one of the rings and ring In at least one ring of and ring A single bond in at least one ring is replaced by a double bond;

[0025] L 1 , L 2 each independently represents a halogen atom;

[0026] X 1 , X 2 Each independently represents -O- or -S-;

[0027] Z 1 Represents a single bond, -CO-O-, -O-CO-, -CH 2 O-、-OCH 2 -、-CH=CH-、-C≡C-、-CH 2 CH 2 -、-CF 2 CF 2 -、

[0028] -(CH 2 ) 4 -、-CF 2 O- or -OCF 2 -;

[0029] n 1 Represents 0, 1, or 2. When n 1 When it indicates 2, the ring Same or different, Z 1 the same or different; and

[0030] n 2 Indicates 0, 1, 2, 3, or 4.

[0031] In the present invention, by designing the specific composition and structure of the compound in the liquid crystal composition, and further by using at least one compound of the general formula I and at least one compound of the general formula II in combination, the obtained liquid crystal composition has a higher K ave Values ​​and higher ε ⊥ / △ε ratio, and has high transmittance and contrast, and also has excellent low-temperature storage performance.

[0032] In the present invention, the halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom (the same below).

[0033] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0034] In some embodiments of the present invention, the compound of formula I is any one or a combination of at least two of the compounds having the following structures:

[0035] as well as

[0036]

[0037] Among them, the ring X 1 , X 2 , L 1 , L 2 , Z 1 , R 1 Has the same protection scope as above.

[0038] In some embodiments of the present invention, the ring express

[0039] In some embodiments of the present invention, the compound of formula I is a compound having the formula I-1.

[0040] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of general formula I is 0.1% to 20%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and is further preferably 1% to 10%.

[0041] In some embodiments of the present invention, it is preferred to adjust the content of the compound of formula I so that the liquid crystal composition containing it has a higher K ave Value, higher ε ⊥ / △ε ratio, high transmittance and contrast, and excellent low-temperature storage performance.

[0042] In some embodiments of the present invention, the compound of formula II-1 is any one or a combination of at least two of the compounds having the following structures:

[0043] as well as

[0044]

[0045] Among them, the R 21 , R 31 、n 2 Has the same scope of protection as above;

[0046] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of general formula II-1 is 0.1% to 20%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and is more preferably 1% to 10%.

[0047] In some embodiments of the present invention, the compound of formula II-2 is any one or a combination of at least two of the compounds having the following structures:

[0048] as well as

[0049]

[0050] Among them, the R 22 , R 32 Has the same scope of protection as above;

[0051] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of general formula II-2 is 0.1% to 20%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and is more preferably 1% to 10%.

[0052] In some embodiments of the present invention, the liquid crystal composition comprises at least one compound of Formula II-1 and Formula II-2.

[0053] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compounds of the general formula II-1 and the general formula II-2 is 0.1% to 30%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, etc., and further preferably 1% to 15%.

[0054] In some embodiments of the present invention, it is preferred to adjust the content of the compound of formula II-1 and / or the compound of formula II-2 so that the liquid crystal composition containing them has a higher K ave Value, higher ε ⊥ / △ε ratio, high transmittance and contrast, and excellent low-temperature storage performance.

[0055] In some embodiments of the present invention, the liquid crystal composition further comprises at least one compound of formula III:

[0056]

[0057] Among them, R 2 represents a straight-chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, a branched-chain alkyl group containing 3 to 12 (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, wherein the straight chain alkyl group contains 1 to 12 carbon atoms, the branched chain alkyl group contains 3 to 12 carbon atoms, One or at least two non-adjacent -CH 2 - may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms may be independently replaced by -F or -Cl;

[0058] Z 2 Represents a single bond, -CH 2 CH 2 -、-CF 2 CF 2 -, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH 2 O- or -OCH 2 -;

[0059] X 3Indicates -O- or -CH 2 -;

[0060] X 4 indicates -F or -H; and

[0061] X 5 It represents a halogen atom, a haloalkyl group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkoxy group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkenyl group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms, or a haloalkenyloxy group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms.

[0062] In some embodiments of the present invention, the liquid crystal composition comprises at least one (eg, two, three, four, five, or six) Z 2 A compound of formula III representing a single bond.

[0063] In some embodiments of the present invention, the liquid crystal composition comprises at least one (eg, two or three) Z 2 Indicates -CH 2 CH 2 -a compound of the general formula III.

[0064] In some embodiments of the present invention, the liquid crystal composition comprises at least one (eg, two, three, four, five, or six) Z 2 A compound of the general formula III representing a single bond, and at least one (eg, two or three) Z 2 Indicates -CH 2 CH 2 -a compound of the general formula III.

[0065] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of formula III is 0.1% to 20%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and more preferably 5% to 15%.

[0066] In some embodiments of the present invention, it is preferred to adjust the content of the compound of formula III so that the liquid crystal composition containing it has a higher K ave Value, higher ε ⊥ / △ε ratio, high transmittance and contrast, and excellent low-temperature storage performance.

[0067] In some embodiments of the present invention, the liquid crystal composition further comprises at least one compound of the general formula N:

[0068]

[0069] Among them, R N1 and R N2 Each independently represents a straight-chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, a branched-chain alkyl group containing 3 to 12 (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, wherein one or at least two non-adjacent -CH 2 - may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0070] ring and ring Each independently expresses in One or at least two of the 2 - can be replaced by -O-, and the single bonds in one or at least two rings can be replaced by double bonds; One or at least two -H in the ring can be replaced by -F, -Cl or -CN independently, and one or at least two -CH= in the ring can be replaced by -N=;

[0071] Z N1 and Z N2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH 2 O-、-OCH 2 -、-CH=CH-、-C≡C-、-CH 2 CH 2 -、-CF 2 CF 2 -、-(CH 2 ) 4 -、-CF 2 O- or -OCF 2 -;

[0072] L N1 and L N2 Each independently represents -H, an alkyl group containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms, or a halogen atom; and

[0073] n N1 Represents 0, 1, 2, or 3, n N2Represents 0 or 1, and 0≤n N1 +n N2 ≤3, where n N1 When it means 2 or 3, the ring Same or different, Z N1 Same or different.

[0074] In some embodiments of the present invention, the compound of the general formula N is any one or a combination of at least two of the compounds having the following structures:

[0075]

[0076]

[0077]

[0078] as well as

[0079]

[0080] Among them, the R N1 and R N2 Has the same protection scope as above.

[0081] In some embodiments of the present invention, the compound of formula N is selected from the group consisting of a compound of formula N-12, a compound of formula N-19, and a compound of formula N-21.

[0082] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of the general formula N is 0.1% to 20%, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and is further preferably 2% to 15%.

[0083] In some embodiments of the present invention, the liquid crystal composition further comprises a group consisting of at least one compound of the general formula A-1 and at least one compound of the general formula A-2:

[0084]

[0085] Among them, R A1 and R A2 Each independently represents a straight-chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, a branched-chain alkyl group containing 3 to 12 (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, Among them, the straight chain alkyl group containing 1 to 12 carbon atoms, the branched chain alkyl group containing 3 to 12 carbon atoms, One or at least two non-adjacent -CH 2 - may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms may be independently replaced by -F or -Cl;

[0086] ring express in and One or at least two of the 2 - can be replaced by -O-; One or at least two single bonds in the rings may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=;

[0087] ring express in One or at least two of the 2 - may be replaced by -O-, and the single bonds in one or at least two rings may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=;

[0088] ring and ring Each independently expresses in One or at least two of the 2 - can be replaced by -O-, One or at least two single bonds in the rings may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=;

[0089] Z A11 , Z A21 and Z A22 Each independently represents a single bond, -CH 2 CH 2 -、-CF 2 CF2 -, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH 2 O- or -OCH 2 -;

[0090] L A11 , L A12 , L A13 , L A21 and L A22 Each independently represents -H, an alkyl group containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms, or a halogen atom;

[0091] X A1 and X A2 each independently represents a halogen atom, a haloalkyl group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkoxy group having 1 to 5 (e.g., 1, 2, 3, 4 or 5) carbon atoms, a haloalkenyl group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms or a haloalkenyloxy group having 2 to 5 (e.g., 2, 3, 4 or 5) carbon atoms;

[0092] n A11 represents 0, 1, 2, or 3, where n A11 When it means 2 or 3, the ring Same or different, Z A11 Same or different;

[0093] n A12 represents 1 or 2, where n A12 When it indicates 2, the ring the same or different; and

[0094] n A2 represents 0, 1, 2, or 3, where n A2 When it means 2 or 3, the ring Same or different, Z A21 Same or different.

[0095] In some embodiments of the present invention, the compound of the general formula A-1 is any one or a combination of at least two of the compounds having the following structures:

[0096]

[0097]

[0098] Among them, the R A1represents a straight chain alkyl group containing 1 to 8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms, a branched chain alkyl group containing 3 to 8 (e.g., 3, 4, 5, 6, 7 or 8) carbon atoms, wherein one or at least two non-adjacent -CH 2 - may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 8 carbon atoms or the branched-chain alkyl group containing 3 to 8 carbon atoms may be independently replaced by -F or -Cl;

[0099] R v and R w Each independently represents -CH 2 -or-O-;

[0100] v and w each independently represent 0 or 1;

[0101] L A11 , L A12 , L A11 ', L A12 ', L A14 , L A15 and L A16 Each independently represents -H or -F;

[0102] L A13 and L A13 'Each independently represents -H or -CH 3 ;and

[0103] The X A1 Indicates -F, -CF 3 or -OCF 3 .

[0104] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of the general formula A-1 is 0.1% to 20%, for example, it can be 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 20%, etc., and is more preferably 4% to 15%.

[0105] In some embodiments of the present invention, by controlling the content of the compound of general formula A-1 within a specific range, the obtained liquid crystal composition has appropriate optical anisotropy, appropriate clearing point, appropriate absolute value of dielectric anisotropy, large K ave value, smaller rotational viscosity, shorter response time, higher transmittance, higher contrast and longer low temperature storage time.

[0106] In some embodiments of the present invention, the compound of formula A-2 is any one or a combination of at least two of the compounds having the following structures:

[0107]

[0108]

[0109] as well as

[0110]

[0111] Among them, the R A2 represents a straight-chain alkyl group containing 1 to 8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms, or a branched-chain alkyl group containing 3 to 8 (e.g., 3, 4, 5, 6, 7 or 8) carbon atoms, wherein one or at least two non-adjacent -CH 2 - may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 8 carbon atoms or the branched-chain alkyl group containing 3 to 8 carbon atoms may be independently replaced by -F or -Cl;

[0112] L A21 , L A22 , L A23 , L A24 and L A25 each independently represents -H or -F; and

[0113] The X A2 Indicates -F, -CF 3 、-OCF 3 or -CH 2 CH 2 CH=CF 2 .

[0114] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of general formula A-2 is 0.1% to 20%, for example, it can be 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, and more preferably 1% to 10%.

[0115] In some embodiments of the present invention, by controlling the content of the compound of formula A-2 within a specific range, the obtained liquid crystal composition has appropriate optical anisotropy, appropriate clearing point, appropriate absolute value of dielectric anisotropy, large Kave value, smaller rotational viscosity, shorter response time, higher transmittance, higher contrast and longer low temperature storage time.

[0116] In some embodiments of the present invention, in the liquid crystal composition, the sum of the weight percentages of the compound of the general formula A-1 and the compound of the general formula A-2 is 0.1% to 30%, for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.

[0117] In some embodiments of the present invention, the liquid crystal composition further comprises at least one compound of the general formula M:

[0118]

[0119] Among them, R M1 and R M2 Each independently represents a straight-chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, a branched-chain alkyl group containing 3 to 12 (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, wherein one or at least two non-adjacent -CH 2 - may each independently be replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0120] ring ring and ring Each independently expresses in One or at least two of the 2 - can be replaced by -O-; At most one -H in can be replaced by a halogen atom;

[0121] Z M1 and Z M2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH 2 O-、-OCH 2 -、-C≡C-、-CH=CH-、-CH 2 CH 2 -or-(CH 2 ) 4 -;and

[0122] n Mrepresents 0, 1, or 2, where n M When it indicates 2, the ring Same or different, Z M2 Same or different.

[0123] In some embodiments of the present invention, the compound of the general formula M is any one or a combination of at least two of the compounds having the following structures:

[0124]

[0125] as well as

[0126]

[0127] Among them, the R M1 and R M2 Has the same protection scope as above.

[0128] In some embodiments of the present invention, the compound of general formula M is selected from the group consisting of compounds of general formula M-1, compounds of general formula M-2, compounds of general formula M-3, compounds of general formula M-10, compounds of general formula M-11, and compounds of general formula M-13.

[0129] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the compound of the general formula M is 20% to 80%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., and is more preferably 40% to 68%.

[0130] In some embodiments of the present invention, the liquid crystal composition further comprises at least one additive.

[0131] The additives include nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, dopant, antioxidant, ultraviolet absorber, infrared absorber, polymerizable monomer or light stabilizer.

[0132] In some embodiments of the present invention, the dopant is selected from any one or a combination of at least two of the following compounds:

[0133]

[0134] as well as

[0135]

[0136] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the dopant is 0% to 5%, for example, it can be 0%, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc., and more preferably 0.01%-1%.

[0137] In some embodiments of the present invention, the antioxidant, light stabilizer, ultraviolet absorber and other additives are preferably the following compounds:

[0138]

[0139]

[0140]

[0141] Herein, n represents a positive integer of 1-12, for example, it can be 1, 2, 4, 6, 8, 9, 10, 11 or 12, etc.

[0142] In some embodiments of the present invention, the antioxidant is selected from any one or a combination of at least two of the following compounds:

[0143]

[0144] In some embodiments of the present invention, in the liquid crystal composition, the weight percentage of the light stabilizer is 0% to 5%, for example, it can be 0%, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc., and more preferably 0.01% to 1%.

[0145] It should be noted that, for the convenience of calculation, in the present invention, the sum of the weight percentages of compounds with different general formulas in the liquid crystal composition is 100%, and the content of additives is not included in the total content of the liquid crystal composition, that is, the addition of additives will make the total content of each component in the liquid crystal composition greater than 100%.

[0146] In some embodiments of the present invention, the liquid crystal composition further includes a polymerization initiator, which illustratively includes but is not limited to: benzoin ethers, benzophenones, acetophenones, benzil ketals, acylphosphine oxides, and the like.

[0147] In a second aspect, the present invention provides a liquid crystal display device, comprising the liquid crystal composition as described in the first aspect.

[0148] Compared with the prior art, the present invention has the following beneficial effects:

[0149] In the present invention, by designing the specific composition and structure of the compound in the liquid crystal composition, and further by using compounds with different general formulas together, the obtained liquid crystal composition has appropriate optical anisotropy, appropriate clearing point, appropriate dielectric anisotropy (ε ⊥ , ε ∥ or Δε), higher K ave Value, higher ε ⊥ / △ε ratio, higher penetration rate, smaller rotational viscosity and longer low-temperature storage time. DETAILED DESCRIPTION

[0150] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0151] For ease of expression, in the following examples, the group structures of the liquid crystal compositions are represented by the codes listed in Table 1:

[0152] Table 1

[0153]

[0154]

[0155] In Table 1, the dotted lines represent the insertion sites of the groups.

[0156] Take the following compound as an example:

[0157]

[0158] The structural formula can be expressed as follows: nCCGF, where n represents the number of carbon atoms in the left alkyl group. For example, if n is "3", it means that the alkyl group is -C 3 H 7 ; In the code, C represents cyclohexyl, G represents 2-fluoro-1,4-phenylene, and F represents fluorine.

[0159] In the following examples and comparative examples, the abbreviations of the performance test items are shown in Table 2:

[0160] Table 2 Abbreviation codes for performance test items

[0161] Test project code meaning Cp Clearing point (nematic-isotropic phase transition temperature, °C) Δn Optical anisotropy (589nm, 20℃) Δε Dielectric anisotropy (1KHz, 20℃) <![CDATA[ε ⊥ ]]> Dielectric constant perpendicular to the molecular axis (1KHz, 20℃) <![CDATA[ε ∥ ]]> Dielectric constant parallel to the molecular axis (1KHz, 20℃) LTS(-30℃) Low temperature storage stability (stored at -30°C and observed crystal precipitation time, h) <![CDATA[K ave ]]> Average elastic constant (20℃) <![CDATA[γ 1 ]]> Rotational viscosity (20℃, mPa·s) <![CDATA[T r ]]> Penetration rate (%)

[0162] Wherein: Cp (℃): tested by melting point instrument quantitative method;

[0163] Δn: measured using an Abbe refractometer under a sodium lamp (589nm) at 20°C, Δn = n e -no , n o is the refractive index of ordinary light, n e is the refractive index of extraordinary light;

[0164] Δε:Δε=ε ∥ -ε ⊥ , where ε ∥ is the dielectric constant parallel to the molecular axis, ε ⊥ is the dielectric constant perpendicular to the molecular axis, the test conditions are 20°C, 1kHz, the test box is a TN box, and the box thickness is 7μm;

[0165] γ 1 : Tested using LCM-2 liquid crystal property evaluation system; test conditions: 20℃, 160-240V, test box thickness 20μm.

[0166] K ave :K ave =(K 11 +K 22 +K 33 ) / 3, where K 11 is the elastic constant of the exhibition area, K 22 is the torsional elastic constant, K 33 is the bending elastic constant, K 11 , K 22 , K 33 The capacitance-voltage characteristic curve (CV curve) of the liquid crystal material is tested and calculated using an LCR meter and an anti-parallel friction cell. The test conditions are: 7 μm anti-parallel friction cell, V=0.1~20V.

[0167] T r : Use DMS 505 photoelectric comprehensive tester to test the VT curve of the dimming device, take the maximum transmittance on the VT curve as the transmittance of the liquid crystal, the test box uses a positive 3.5μm IPS test box, V=0~20V.

[0168] LTS (-30℃): The nematic liquid crystal medium is placed in a 3.5um IPS test box anti-parallel box and stored at a constant temperature of -30℃. The time when crystal precipitation is observed is recorded, where 168h NG means crystallization after storage for 168h, 168h OK means no crystallization after storage for 168h, and 240h OK means no crystallization after storage for 240h.

[0169] Example 1

[0170] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0171]

[0172] Among them, the structural formula of 5PGP(NA) is

[0173] Example 2

[0174] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0175]

[0176]

[0177] Example 3

[0178] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0179]

[0180] Example 4

[0181] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0182]

[0183] Example 5

[0184] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0185]

[0186] Example 6

[0187] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0188]

[0189] Comparative Example 1

[0190] This comparative example provides a liquid crystal composition, which includes components in percentage by mass as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0191]

[0192] Comparative Example 2

[0193] This comparative example provides a liquid crystal composition, which includes components in percentage by mass as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0194]

[0195] From the comparison between Comparative Example 1-2 and Example 6, it can be seen that the liquid crystal composition of the present invention has appropriate optical anisotropy, appropriate clearing point, appropriate dielectric anisotropy (ε ⊥ , ε ∥ , ε ⊥ / Δε), higher K ave value, higher transmittance, smaller rotational viscosity and better low temperature storage stability.

[0196] Example 7

[0197] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0198]

[0199]

[0200] Example 8

[0201] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0202]

[0203] Example 9

[0204] This embodiment provides a liquid crystal composition, which includes components in weight percentage as shown in the following table, and is filled between two substrates of a liquid crystal display for performance testing:

[0205]

[0206]

[0207] From the above content, it can be seen that in the present invention, by designing the specific composition and structure of the compound in the liquid crystal composition, and further by using compounds with different general formulas together, the obtained liquid crystal composition has appropriate optical anisotropy, appropriate clearing point, lower rotational viscosity, higher K ave Values ​​and higher ε ⊥ / △ε ratio, and has high transmittance and contrast, and also has excellent low-temperature storage performance.

[0208] The applicant declares that the present invention illustrates the liquid crystal composition and liquid crystal display device of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A liquid crystal composition, characterized in that: The liquid crystal composition comprises at least one compound of formula I-1 and at least one compound selected from formula II-1 and / or formula II-2: wherein R1 represents -H, a halogenated or unhalogenated straight-chain alkyl group containing 1 to 12 carbon atoms, a halogenated or unhalogenated branched-chain alkyl group containing 3 to 12 carbon atoms, a halogenated or unhalogenated alkoxy group containing 1 to 12 carbon atoms, a halogenated or unhalogenated alkenyl group containing 2 to 12 carbon atoms, a halogenated or unhalogenated alkenyloxy group containing 2 to 12 carbon atoms, R 21 and R 32 Each independently represents an alkyl group containing 1 to 12 carbon atoms, an alkoxy group containing 1 to 12 carbon atoms, an alkenyl group containing 2 to 12 carbon atoms, or an alkenyloxy group containing 2 to 12 carbon atoms; R 22 represents a halogen atom, a haloalkyl group containing 1 to 5 carbon atoms, a haloalkoxy group containing 1 to 5 carbon atoms, a haloalkenyl group containing 2 to 5 carbon atoms, or a haloalkenyloxy group containing 2 to 5 carbon atoms; R 31 represents -H, an alkyl group containing 1 to 12 carbon atoms, or an alkoxy group containing 1 to 12 carbon atoms; ring express ring ring ring and ring Each independently expresses Said One or at least two -CH2- in the ring may be replaced by -O-, a single bond in one or at least two rings may be replaced by a double bond, and at least one of the rings and ring In at least one ring of and ring A single bond in at least one ring is replaced by a double bond; L1 and L2 represent fluorine atoms; X1 represents -O-; X2 represents -O- or -S-; n2 represents 0, 1, 2, 3 or 4; The weight percentage of the compound of formula I-1 is 0.1% to 20%; The weight percentage of the compound of formula II-1 is 0.1% to 20%; The weight percentage of the compound of formula II-2 is 0.1% to 20%; The liquid crystal composition further comprises at least one compound of formula III: Wherein, R2 represents a straight chain alkyl group containing 1 to 12 carbon atoms, a branched chain alkyl group containing 3 to 12 carbon atoms, wherein the straight chain alkyl group containing 1 to 12 carbon atoms, the branched chain alkyl group containing 3 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the group may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms may be independently replaced by -F or -Cl; Z2 represents a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH2O- or -OCH2-; X3 represents -O- or -CH2-; X4 represents -F or -H; and X5 represents a halogen atom, a haloalkyl group containing 1 to 5 carbon atoms, a haloalkoxy group containing 1 to 5 carbon atoms, a haloalkenyl group containing 2 to 5 carbon atoms, or a haloalkenyloxy group containing 2 to 5 carbon atoms; The weight percentage of the compound of formula III is 0.1% to 20%; The liquid crystal composition further comprises a group consisting of at least one compound of the general formula A-1 and at least one compound of the general formula A-2: Among them, R A1 and R A2 Each independently represents a straight chain alkyl group containing 1 to 12 carbon atoms, a branched chain alkyl group containing 3 to 12 carbon atoms, Among them, the straight chain alkyl group containing 1 to 12 carbon atoms, the branched chain alkyl group containing 3 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the group may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms may be independently replaced by -F or -Cl; ring express in One or at least two -CH2- in the mixture may be replaced by -O-; One or at least two single bonds in the rings may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=; ring express in One or at least two -CH2- in the ring may be replaced by -O-, and one or at least two single bonds in the ring may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=; ring and ring Each independently expresses in One or at least two -CH2- in the One or at least two single bonds in the rings may be replaced by double bonds; One or at least two -H in the ring may be independently replaced by -F, -Cl or -CN, and one or at least two -CH= in the ring may be replaced by -N=; Z A11 , Z A21 and Z A22 each independently represents a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH2O- or -OCH2-; L A11 , L A12 , L A13 , L A21 and L A22 Each independently represents -H, an alkyl group containing 1 to 3 carbon atoms or a halogen atom; X A1 and X A2 Each independently represents a halogen atom, a haloalkyl group containing 1 to 5 carbon atoms, a haloalkoxy group containing 1 to 5 carbon atoms, a haloalkenyl group containing 2 to 5 carbon atoms, or a haloalkenyloxy group containing 2 to 5 carbon atoms; n A11 represents 0, 1, 2, or 3, where n A11 When it means 2 or 3, the ring Same or different, Z A11 Same or different; n A12 represents 1 or 2, where n A12 When it indicates 2, the ring the same or different; and n A2 represents 0, 1, 2, or 3, where n A2 When it means 2 or 3, the ring Same or different, Z A21 Same or different; The weight percentage of the compound of the general formula A-1 is 0.1% to 20%; In the liquid crystal composition, the weight percentage of the compound of the general formula A-2 is 0.1% to 20%; The liquid crystal composition further includes at least one compound of the general formula M: Among them, R M1 and R M2 Each independently represents a straight chain alkyl group containing 1 to 12 carbon atoms, a branched chain alkyl group containing 3 to 12 carbon atoms, wherein one or at least two non-adjacent -CH2- in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; ring ring and ring Each independently expresses in One or at least two -CH2- in can be replaced by -O-; At most one -H in can be replaced by a halogen atom; Z M1 and Z M2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CH2CH2- or -(CH2)4-; and n M represents 0, 1, or 2, where n M When it indicates 2, the ring Same or different, Z M2 Same or different; In the liquid crystal composition, the weight percentage of the compound of the general formula M is 20%-80%.

2. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of formula I-1 is 1% to 10%.

3. The liquid crystal composition according to claim 1, characterized in that: The compound of the general formula II-1 is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R 21 , R 31 , n2 has the same protection scope as claim 1.

4. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of formula II-1 is 1% to 10%.

5. The liquid crystal composition according to claim 1, characterized in that: The compound of the general formula II-2 is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R 22 , R 32 It has the same protection scope as claim 1.

6. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of formula II-2 is 1% to 10%.

7. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the total weight percentage of the compounds of the general formula II-1 and the general formula II-2 is 0.1% to 30%.

8. The liquid crystal composition according to claim 7, characterized in that: In the liquid crystal composition, the total weight percentage of the compounds of the general formula II-1 and the general formula II-2 is 1% to 15%.

9. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of formula III is 5% to 15%.

10. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises at least one compound of the general formula N: Among them, R N1 and R N2 Each independently represents a straight chain alkyl group containing 1 to 12 carbon atoms, a branched chain alkyl group containing 3 to 12 carbon atoms, wherein one or at least two non-adjacent -CH2- in the straight-chain alkyl group containing 1 to 12 carbon atoms or the branched-chain alkyl group containing 3 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; ring and ring Each independently expresses in One or at least two -CH2- in the ring can be replaced by -O-, and one or at least two single bonds in the ring can be replaced by double bonds; One or at least two -H in the ring can be replaced by -F, -Cl or -CN independently, and one or at least two -CH= in the ring can be replaced by -N=; Z N1 and Z N2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-; L N1 and L N2 Each independently represents -H, an alkyl group containing 1 to 3 carbon atoms, or a halogen atom; and n N1 Indicates 0, 1, 2, or 3, n N2 Represents 0 or 1, and 0≤n N1 +n N2 ≤3, where n N1 When it means 2 or 3, the ring Same or different, Z N1 Same or different.

11. The liquid crystal composition according to claim 10, characterized in that: The compound of the general formula N is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R N1 and R N2 It has the same protection scope as claim 10.

12. The liquid crystal composition according to claim 11, characterized in that: The compound of the general formula N is any one or a combination of two of the compounds having the following structures: as well as Among them, the R N1 and R N2 It has the same protection scope as claim 10.

13. The liquid crystal composition according to claim 10, characterized in that: In the liquid crystal composition, the weight percentage of the compound of the general formula N is 0.1% to 20%.

14. The liquid crystal composition according to claim 13, characterized in that: In the liquid crystal composition, the weight percentage of the compound of the general formula N is 2% to 15%.

15. The liquid crystal composition according to claim 1, characterized in that: The compound of the general formula A-1 is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R A1 represents a straight chain alkyl group containing 1 to 8 carbon atoms, a branched chain alkyl group containing 3 to 8 carbon atoms, wherein one or at least two non-adjacent -CH2- in the straight-chain alkyl group containing 1 to 8 carbon atoms or the branched-chain alkyl group containing 3 to 8 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1 to 8 carbon atoms or the branched-chain alkyl group containing 3 to 8 carbon atoms can be independently replaced by -F or -Cl; R v and R w Each independently represents -CH2- or -O-; v and w each independently represent 0 or 1; L A11 , L A12 , L A11 ',L A12 ',L A14 , L A15 and L A16 Each independently represents -H or -F; L A13 and L A13 ' each independently represents -H or -CH3; and The X A1 It represents -F, -CF3 or -OCF3.

16. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of the general formula A-1 is 4% to 15%.

17. The liquid crystal composition according to claim 1, characterized in that: The compound of the general formula A-2 is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R A2 represents a straight-chain alkyl group containing 1-8 carbon atoms or a branched-chain alkyl group containing 3-8 carbon atoms, wherein one or at least two non-adjacent -CH2- in the straight-chain alkyl group containing 1-8 carbon atoms or the branched-chain alkyl group containing 3-8 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or at least two -H in the straight-chain alkyl group containing 1-8 carbon atoms or the branched-chain alkyl group containing 3-8 carbon atoms can be independently replaced by -F or -Cl; L A21 , L A22 , L A23 , L A24 and L A25 each independently represents -H or -F; and The X A2 It represents -F, -CF3, -OCF3 or -CH2CH2CH=CF2.

18. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of the general formula A-2 is 1% to 10%.

19. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the sum of the weight percentages of the compound of the general formula A-1 and the compound of the general formula A-2 is 0.1% to 30%.

20. The liquid crystal composition according to claim 1, characterized in that: The compound of the general formula M is any one or a combination of at least two of the compounds having the following structures: as well as Among them, the R M1 and R M2 It has the same protection scope as claim 1.

21. The liquid crystal composition according to claim 20, characterized in that: The compound of the general formula M is any one or a combination of at least two of the compounds having the following structures: as well as 22. The liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the weight percentage of the compound of the general formula M is 40% to 68%.

23. A liquid crystal display device, characterized in that: The liquid crystal display device comprises the liquid crystal composition according to any one of claims 1 to 22.

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