Liquid crystal composition and liquid crystal display device containing the same

Abstract

The present invention provides a liquid crystal composition and a liquid crystal display device comprising the same, wherein the liquid crystal composition comprises at least one compound of formula I, at least one compound of formula II and at least one compound of formula III. By selecting and compounding the components, the liquid crystal composition has a suitable clearing point and a suitable dielectric anisotropy, and also has a larger optical anisotropy and a larger average elastic constant K ave , higher vertical dielectric to dielectric ratio, lower rotational viscosity γ1, higher transmittance and contrast, longer low-temperature storage time and better low-temperature storage stability, faster response speed of liquid crystal materials, suitable for fast-response IPS, TN, VA, NFFS and other display modes.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid crystal materials, and in particular relates to a liquid crystal composition and a liquid crystal display device comprising the same. 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. In addition, new display modes include, for example, UV2A (Ultra Violet Vertical Alignment), PSVA (Polymer Stabilized Vertical Alignment), NFFS (Negativityfringe field switching), etc.

[0003] In the early 1970s, the industry had conducted experimental research on the basic electro-optical properties of uniformly arranged and twistedly arranged nematic phase liquid crystal IPS mode. Its characteristics are 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 is also called the lateral field mode. In the IPS mode, the nematic phase liquid crystal molecules are arranged uniformly and parallel between the two substrates, and the two polarizers are placed orthogonally. When the IPS mode is not applied with an electric field, the incident light is blocked by the two orthogonal polarizers and is in a dark state. When the electric field is applied, the liquid crystal molecules rotate and cause a delay, so light leaks from the two orthogonal polarizers. The advantages of the panel using the IPS mode are a large viewing angle and accurate color reproduction, but the disadvantages are serious light leakage and slow response speed.

[0004] With the widespread application of TFT LCD (thin film transistor liquid crystal display technology), the requirements for its performance are also constantly increasing. High display image quality requires it to have 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, technicians in this field 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 which light scattering accounts for 63% of the factors affecting light leakage performance.

[0007] According to the following relationship: Where d is the spacing of the liquid crystal cell, n e represents the extraordinary refractive index, n o represents the ordinary refractive index.

[0008] To improve the light scattering of liquid crystal materials, it is necessary to increase the average elastic constant K ave To improve light scattering, K ave =(K 11 +K 22 +K 33 )÷3; in increasing K ave In this case, light leakage of the liquid crystal material can be reduced.

[0009] In addition, the relationship between contrast (CR) and brightness (L) is as follows: CR = L 255 / L0×100%; where L 255 L0 is the brightness of the on state, and L0 is the brightness of the off state. It can be seen that the change of L0 should significantly affect CR. In the off state, L0 has nothing to do with the dielectric properties of the liquid crystal molecules, but is related to the LC Scattering of the liquid crystal material itself; the smaller the LC Scattering, the smaller the L0, and the CR will be significantly improved.

[0010] 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 makes the liquid crystal molecules more ordered and less light leaks, thereby improving the transmittance.

[0011] However, the liquid crystal materials in the prior art generally have ε ⊥ The small ratio of / Δε and low K value lead to defects such as insufficient transmittance, slow response, and poor low-temperature storage performance. When modulating the liquid crystal composition, appropriate liquid crystal monomers are selected and mixed in a certain proportion to obtain a liquid crystal composition that meets different display requirements. A single liquid crystal monomer can improve some properties of the mixed liquid crystal, but it also has an adverse effect on other properties of the liquid crystal composition. Therefore, modulating a liquid crystal composition that meets various performance requirements is still an urgent problem to be solved.

[0012] Therefore, an average elastic constant K is developed ave Liquid crystal materials with high viscosity, low rotational viscosity, high transmittance and fast response speed are problems to be solved urgently in this field. Summary of the invention

[0013] In view of the deficiencies in the prior art, the object of the present invention is to provide a liquid crystal composition and a liquid crystal display device comprising the same, wherein the liquid crystal composition has a greater optical anisotropy, a higher ratio of perpendicular dielectric to dielectric, a larger average elastic constant, a higher transmittance and response speed, a lower rotational viscosity and better low-temperature storage stability while maintaining a suitable clearing point and appropriate dielectric anisotropy.

[0014] To achieve this object, the present invention adopts the following technical solutions:

[0015] In a first aspect, the present invention provides a liquid crystal composition, comprising:

[0016] At least one compound of formula I:

[0017]

[0018] At least one compound of formula II:

[0019]

[0020] At least one compound of formula III:

[0021]

[0022] wherein R0, R1 and R2 each independently represent a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group can be independently replaced by -F or -Cl;

[0023] R X represents a haloalkyl group containing 1-5 (e.g., 1, 2, 3, 4, or 5) carbon atoms, a haloalkoxy group containing 1-4 (e.g., 1, 2, 3, or 4) carbon atoms, or a straight-chain or branched alkyl group containing 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms; one or at least two non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1-12 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O-, or -O-CO-;

[0024] R3 represents halogen, halogenated or unsubstituted alkenyl containing 2-8 (e.g. 2, 3, 4, 5, 6, 7 or 8) carbon atoms, halogenated or unsubstituted alkenyloxy containing 2-7 (e.g. 2, 3, 4, 5, 6 or 7) carbon atoms;

[0025] ring and ring Each independently expresses or one or at least two rings with single bonds replaced by double bonds And at most one ring or ring express

[0026] Y1 represents -H or halogen;

[0027] X1 represents halogen, haloalkyl containing 1-5 (e.g. 1, 2, 3, 4 or 5) carbon atoms, haloalkoxy containing 1-5 (e.g. 1, 2, 3, 4 or 5) carbon atoms, haloalkenyl containing 2-5 (e.g. 2, 3, 4 or 5) carbon atoms, or haloalkenyloxy containing 2-5 (e.g. 2, 3, 4 or 5) carbon atoms;

[0028] n represents 0 or 1.

[0029] The liquid crystal composition provided by the present invention is a liquid crystal composition with positive dielectric anisotropy, which is compounded by a compound of formula I containing a cyclohexene structure with a compound of formula II and a compound of formula III, so that the liquid crystal composition has a suitable clearing point and a suitable dielectric anisotropy, and also has a higher optical anisotropy (refractive index), a larger average elastic constant K ave , a higher ratio of vertical dielectric to dielectric (ε ⊥ / Δε), lower rotational viscosity γ1, higher transmittance and contrast, longer low-temperature storage time and better low-temperature storage stability, faster response speed of liquid crystal materials, suitable for fast-response IPS, TN, VA, NFFS and other display modes.

[0030] In the present invention, “may be independently replaced by…” means that it may (can) be replaced or not be replaced, that is, replacement or not being replaced falls within the protection scope of the present invention; the same applies to “may be independently replaced by…”; moreover, the positions of “replacement” and “replacement” are arbitrary.

[0031] In the present invention, the short straight lines on one or both sides of a group represent access bonds, not methyl groups; for example The short straight line on the left, Short straight lines on both sides.

[0032] In the present invention, the halogen includes fluorine, chlorine, bromine or iodine, etc.; when the same description is mentioned below, they have the same meaning.

[0033] In the present invention, the halogenated group means that at least one hydrogen atom in the group is replaced by a halogen (fluorine, chlorine, bromine or iodine).

[0034] In a preferred technical solution, the ring and ring Each independently expresses And at most one ring or ring express

[0035] In a preferred technical solution, the compound of formula I is selected from the group consisting of the following compounds:

[0036]

[0037] as well as

[0038]

[0039] Among them, R X ' represents a straight or branched alkyl group containing 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms.

[0040] In a preferred technical solution, in order to obtain greater optical anisotropy, higher elastic constant K value, higher transmittance and contrast, excellent mutual solubility and low-temperature storage stability, and faster response speed, the compound of formula I is selected from the group consisting of compounds of formula I-1, compounds of formula I-2 and compounds of formula I-9.

[0041] In a preferred technical embodiment, R0 represents a straight-chain alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms or a straight-chain alkenyl group containing 2-8 (e.g., 2, 3, 4, 5, 6, 7 or 8) carbon atoms.

[0042] In a preferred technical solution, the compound of formula II is selected from the group consisting of the following compounds:

[0043] as well as

[0044]

[0045] In a preferred technical solution, in order to obtain a higher elastic constant (K value), higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least one compound of formula II-1 and / or at least one compound of formula II-2.

[0046] In a preferred technical solution, in order to obtain greater optical anisotropy, higher elastic constant (K value), higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least two (for example, 2, 3 or 4, etc.) compounds of formula II, and further preferably contains a combination of at least one compound of formula II-1 and at least one compound of formula II-2.

[0047] In a preferred technical solution, the R1 represents a straight-chain or branched alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms, and one or at least two non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1-8 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned groups can be independently replaced by -F or -Cl; further preferred is a straight-chain alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms.

[0048] In a preferred technical solution, X1 represents -F, -CF3 or -OCF3, and is further preferably -F.

[0049] In a preferred technical solution, the compound of formula III is selected from the group consisting of the following compounds:

[0050]

[0051]

[0052] as well as

[0053]

[0054] In a preferred technical scheme, in order to obtain greater optical anisotropy, higher elastic constant K value, higher perpendicular dielectric to dielectric ratio, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the compound of general formula III is selected from the group consisting of compounds of formula III-1, compounds of formula III-4, and compounds of formula III-8.

[0055] In a preferred technical embodiment, R2 represents a straight-chain alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms or a straight-chain alkenyl group containing 2-8 (e.g., 2, 3, 4, 5, 6, 7 or 8) carbon atoms.

[0056] In a preferred technical solution, the content of the compound of formula I is adjusted so that the liquid crystal composition containing it has appropriate optical anisotropy, suitable clearing point, suitable dielectric anisotropy, higher elastic constant K value, higher transmittance and contrast, excellent mutual solubility and low-temperature storage stability and faster response speed.

[0057] In a preferred technical solution, the mass percentage of the compound of formula I in the liquid crystal composition is 0.1%-30%, for example, it can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 15%, 17%, 19%, 20%, 22%, 25% or 28%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and it is further preferably 1%-12%.

[0058] In a preferred technical solution, the content of the compound of formula II is adjusted so that the liquid crystal composition containing it has appropriate optical anisotropy, suitable clearing point, better dielectric anisotropy, higher elastic constant K value, higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed.

[0059] In a preferred technical solution, the mass percentage of the compound of formula II in the liquid crystal composition is 1%-20%, for example, it can be 2%, 3%, 5%, 7%, 9%, 10%, 11%, 13%, 15%, 17% or 19%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and it is further preferably 4%-12%.

[0060] In a preferred technical solution, the content of the compound of formula III is adjusted so that the liquid crystal composition containing it has appropriate optical anisotropy, suitable clearing point, better dielectric anisotropy, higher elastic constant K value, higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed.

[0061] In a preferred technical solution, the mass percentage of the compound of formula III in the liquid crystal composition is 1%-50%, for example, it can be 2%, 3%, 5%, 7%, 9%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and it is further preferably 5%-40%.

[0062] In a preferred technical solution, the liquid crystal composition further comprises at least one compound selected from the group consisting of compounds of formula A-1 and formula A-2:

[0063]

[0064] Among them, R A1 and R A2 Each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group can be independently replaced by -F or -Cl;

[0065] ring and ring Each independently expresses Said One or at least two non-adjacent -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; -CH= in one or at least two rings may be replaced by -N=; one or at least two -H in the aforementioned groups may be replaced by -F or -Cl;

[0066] ring and ring Each independently expresses Said One or at least two non-adjacent -CH2- can be replaced by -O-; -CH= in one or at least two rings may be replaced by -N=; one or at least two -H in the aforementioned groups may be replaced by -F or -Cl;

[0067] Z A11 , Z A21 and Z A22 Each independently represents a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -C≡C-, -CH=CH-, -CF=CF-, -CH2O- or -OCH2-;

[0068] L A11 , L A12 , L A13 , L A21 and L A22 Each independently represents -H, halogen, unsubstituted or halogenated straight-chain alkyl containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms;

[0069] X A1 and X A2 each independently represents halogen, haloalkyl containing 1-5 (e.g. 1, 2, 3, 4 or 5) carbon atoms, haloalkoxy containing 1-5 (e.g. 1, 2, 3, 4 or 5) carbon atoms, haloalkenyl containing 2-5 (e.g. 2, 3, 4 or 5) carbon atoms or haloalkenyloxy containing 2-5 (e.g. 2, 3, 4 or 5) carbon atoms;

[0070] n A11 and n A2 Each independently represents 0, 1, 2 or 3; when n A11 Represents 2, n A12 Represents 1, Z A11 When all are single bonds, the ring Not for ring Same or different, Z A11 Same or different; when n A11 Indicates 3 o'clock, ring Same or different, Z A11 Same or different; when n A2 When it means 2 or 3, the ring Same or different, Z A21 Same or different;

[0071] n A12 Indicates 1 or 2; when n A12 When it indicates 2, the ring Same or different.

[0072] In a preferred technical solution, the compound of formula A-1 is selected from the group consisting of the following compounds:

[0073]

[0074]

[0075]

[0076] as well as

[0077]

[0078] Among them, R A1 represents a straight or branched alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms; one or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1-8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group may be independently replaced by -F or -Cl;

[0079] R v and R w Each independently represents -CH2- or -O-;

[0080] L A11 , L A12 , L A11 ', L A12 ', L A14 , L A15 and L A16 Each independently represents -H or -F;

[0081] L A13 and L A13 'Each independently represents -H or -CH3;

[0082] X A1 represents -F, -CF3 or -OCF3;

[0083] v and w each independently represent 0 or 1.

[0084] In a preferred technical solution, in order to obtain greater optical anisotropy, higher elastic constant K value, higher perpendicular dielectric to dielectric ratio, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least one compound of formula A-1-14.

[0085] In a preferred technical solution, the compound of formula A-2 is selected from the group consisting of the following compounds:

[0086]

[0087]

[0088]

[0089] as well as

[0090]

[0091] Among them, R A2 represents a straight or branched alkyl group containing 1-8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms; one or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1-8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group may be independently replaced by -F or -Cl;

[0092] L A21 , L A22 , L A23 , L A24 and L A25 Each independently represents -H or -F;

[0093] X A2 It represents -F, -CF3, -OCF3 or -(CH2)2-CH=CF2.

[0094] In a preferred technical solution, the mass percentage of the compound selected from the group consisting of compounds of formula A-1 and formula A-2 in the liquid crystal composition is 0.1%-60%, for example, it can be 0.3%, 0.5%, 0.8%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55% or 58%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0095] In a preferred technical scheme, in order to obtain a higher elastic constant K value, a higher ratio of vertical dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least one compound of formula A-2-12, a compound of formula A-2-13 or a compound of formula A-2-17, or a combination of at least two of them.

[0096] In a preferred technical solution, the mass percentage of the compound of formula A-1 in the liquid crystal composition is 0.1%-50%, for example, it can be 0.3%, 0.5%, 0.8%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0097] In a preferred technical solution, the mass percentage of the compound of formula A-2 in the liquid crystal composition is 0.1%-50%, for example, it can be 0.3%, 0.5%, 0.8%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0098] In a preferred technical solution, the liquid crystal composition further comprises at least one compound of formula M:

[0099]

[0100] Among them, R M1 and R M2 Each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0101] ring ring and ring Each independently expresses Said One or at least two non-adjacent -CH2- can be replaced by -O-; In one or at least two rings, -CH= may be replaced by -N=, and at most one -H may be replaced by halogen;

[0102] Z M1 and Z M2Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CH2CH2- or -(CH2)4-;

[0103] n M Represents 0, 1, or 2;

[0104] When n M When 1 is represented, the compound of formula M does not contain terphenyl (i.e., unsubstituted or halogen-substituted )structure;

[0105] When n M When it indicates 2, the ring Same or different, Z M2 Same or different.

[0106] In a preferred technical solution, the compound of formula M is selected from the group consisting of the following compounds:

[0107]

[0108]

[0109]

[0110] as well as

[0111]

[0112] In a preferred technical scheme, the compound of formula M includes any one or a combination of at least two of the compounds of formula M-1, M-2, M-4, M-10, M-11, M-13, M-14, M-15, M-17, M-21, M-22, M-23 or M-24.

[0113] In a preferred technical scheme, in order to obtain a suitable clearing point, moderate dielectric anisotropy, greater optical anisotropy, a higher elastic constant K value, a higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least one compound of formula M-1 and / or at least one compound of formula M-4; it is further preferred to contain at least one compound of formula M-1 whose terminal group is an alkenyl group.

[0114] In a preferred technical scheme, in order to obtain a suitable clearing point, moderate dielectric anisotropy, greater optical anisotropy, a higher elastic constant K value, a higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed, the liquid crystal composition contains at least one compound of formula M-10, and further preferably contains at least one compound of formula M-10 whose terminal group is an alkenyl group.

[0115] In a preferred technical solution, the R M1 and R M2 Each independently represents a straight-chain alkyl group containing 1 to 8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms, a straight-chain alkoxy group containing 1 to 8 (e.g., 1, 2, 3, 4, 5, 6, 7 or 8) carbon atoms, or a straight-chain alkenyl group containing 2 to 8 (e.g., 2, 3, 4, 5, 6, 7 or 8) carbon atoms, and is more preferably a straight-chain alkyl group containing 1 to 6 carbon atoms or a straight-chain alkenyl group containing 2 to 6 carbon atoms.

[0116] In a preferred technical solution, adjusting the content of the compound of formula M can make the liquid crystal composition have a suitable clearing point, moderate dielectric anisotropy, greater optical anisotropy, higher elastic constant K value, higher ratio of perpendicular dielectric to dielectric, higher transmittance and contrast, excellent low-temperature storage stability and faster response speed.

[0117] In a preferred technical solution, the mass percentage of the compound of formula M in the liquid crystal composition is 0.1%-70%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65% or 68%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0118] In a preferred technical solution, the liquid crystal composition further comprises at least one compound of formula N:

[0119]

[0120] Among them, R N1 and R N2 Each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0121] ring and ring Each independently expresses Said 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; In one or at least two rings, -CH= may be replaced by -N=, and in the aforementioned groups, one or at least two -H may be replaced by -F, -Cl or -CN;

[0122] 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-;

[0123] L N1 and L N2 Each independently represents -H, halogen, unsubstituted or halogenated straight-chain alkyl containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms;

[0124] n N1 Represents 0, 1, 2, or 3, n N2 Represents 0 or 1, and 0≤n N1 +n N2 ≤3; when n N1 When it means 2 or 3, the ring Same or different, Z N1 Same or different.

[0125] In a preferred technical solution, the compound of formula N is selected from the group consisting of the following compounds:

[0126]

[0127]

[0128]

[0129]

[0130] as well as

[0131]

[0132] In a preferred technical scheme, the compound of formula N comprises any one or a combination of at least two of the compounds of formula N-1, N-2, N-3, N-7, N-9, N-12, N-14, N-17, N-19, N-20, N-22, N-27, N-28, N-35, N-37 or N-38.

[0133] In a preferred technical solution, the mass percentage of the compound of formula N in the liquid crystal composition is 0.1%-40%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38% or 40%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0134] In a preferred technical solution, the R N1 and R N2 Each independently represents a straight-chain alkyl group containing 1-8 (e.g. 1, 2, 3, 4, 5 or 6) carbon atoms, a straight-chain alkoxy group containing 1-6 (e.g. 1, 2, 3, 4, 5 or 6) carbon atoms, or a straight-chain alkenyl group containing 2-6 (e.g. 2, 3, 4, 5 or 6) carbon atoms.

[0135] In a preferred technical solution, the liquid crystal composition further comprises at least one compound of formula B:

[0136]

[0137] Among them, R B1 and R B2 Each independently represents -H, halogen, a straight-chain or branched alkyl group containing 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms; one or at least two non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1-12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -S-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned groups can be independently replaced by -F or -Cl;

[0138] ring and ring Each independently expresses Said One or at least two non-adjacent -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; -CH= in one or at least two rings may be replaced by -N=; one or at least two -H in the aforementioned groups may be replaced by -F, -Cl, -CN, -CH3 or -OCH3;

[0139] Z B1 and Z B2 Each independently represents a single bond, -O-, -S-, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-;

[0140] Y B1 and Y B2 Each independently represents -H, halogen, unsubstituted or halogenated straight-chain alkyl containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms, or unsubstituted or halogenated straight-chain alkoxy containing 1 to 3 (e.g., 1, 2 or 3) carbon atoms;

[0141] X B represents -O-, -S-, -CO-, -CF2-, -NH- or -NF-;

[0142] n B1 and n B2 Each independently represents 0, 1 or 2; when n B1 When it indicates 2, the ring Same or different, Z B1 Same or different, when n B2 When it indicates 2, the ring Same or different, Z B2 Same or different.

[0143] In a preferred technical solution, the compound of formula B is selected from the group consisting of the following compounds:

[0144]

[0145]

[0146] as well as

[0147]

[0148] Among them, Y B3 and Y B4Each independently represents -H, -F, -Cl, -CN, -CH3 or -OCH3.

[0149] In a preferred technical solution, the mass percentage of the compound of formula B in the liquid crystal composition is 0.1%-30%, for example, it can be 0.3%, 0.5%, 0.8%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25% or 28%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0150] In addition to the above compounds, the liquid crystal composition of the present invention may also contain common nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, polymerizable monomers or additives.

[0151] In a preferred technical solution, the additive includes any one of a dopant, an antioxidant, an ultraviolet absorber, an infrared absorber or a light stabilizer, or a combination of at least two thereof.

[0152] Possible dopants which are preferably added to the liquid crystal composition of the present invention are shown below:

[0153]

[0154]

[0155] as well as

[0156]

[0157] In some embodiments of the present invention, the weight percentage of the dopant in the liquid crystal composition is 0%-5%; preferably, the weight percentage of the dopant in the liquid crystal composition is 0.01%-1%.

[0158] In addition, the antioxidant, light stabilizer, ultraviolet absorber and other additives used in the liquid crystal composition of the present invention are preferably the following:

[0159]

[0160]

[0161]

[0162] Here, n represents a positive integer from 1 to 12.

[0163] Preferably, the antioxidant is selected from the compounds shown below:

[0164]

[0165] In some embodiments of the present invention, the additive accounts for 0%-5% of the total weight of the liquid crystal composition; preferably, the additive accounts for 0.01%-1% of the total weight of the liquid crystal composition.

[0166] In a second aspect, the present invention provides a liquid crystal display device, comprising the liquid crystal composition as described in one of the purposes.

[0167] Compared with the prior art, the present invention has the following beneficial effects:

[0168] In the liquid crystal composition provided by the present invention, by selecting and compounding the components, the liquid crystal composition has a moderate clearing point and appropriate dielectric anisotropy, and also has a larger optical anisotropy and a larger average elastic constant K ave , higher vertical dielectric to dielectric ratio, lower rotational viscosity γ1, higher transmittance and contrast, longer low-temperature storage time and better low-temperature storage stability, faster response speed of liquid crystal materials, suitable for fast-response IPS, TN, VA, NFFS and other display modes. DETAILED DESCRIPTION

[0169] The technical solution of the present invention is further described below by specific implementation methods. 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.

[0170] For ease of expression, in the following embodiments and comparative examples, the group structures of the components in the liquid crystal composition are represented by the codes listed in Table 1:

[0171] Table 1

[0172]

[0173]

[0174] Take the following compound as an example:

[0175] The structure is represented by the code listed in Formula I, which can be expressed as: nDPUQUF; wherein D represents 1,3-dioxane-2,5-diyl, P represents 1,4-phenylene, U represents 2,6-difluoro-1,4-phenylene, Q represents a difluoroether group, F represents the F on the right end, and n represents the number of carbon atoms of the alkyl group on the left end. For example, if n is "3", it means that the alkyl group is a n-propyl group.

[0176] The abbreviations of the test items in the following embodiments and comparative examples are as follows:

[0177] Cp clearing point (nematic-isotropic phase transition temperature, °C)

[0178] Δn optical anisotropy (589nm, 20℃)

[0179] ε ⊥ Dielectric constant perpendicular to the molecular axis (1kHz, 20℃)

[0180] Δε Dielectric anisotropy (1kHz, 20℃)

[0181] ε ⊥ / Δε Ratio of perpendicular dielectric to dielectric

[0182] K ave Average elastic constant (20℃)

[0183] Tr(%) Transmission rate(%,20℃)

[0184] γ1 Rotational viscosity (mPa·s, 20℃)

[0185] LTS (-30℃) Low temperature storage time (-30℃, h)

[0186] Wherein, Cp: measured by MP70 melting point instrument;

[0187] Δn: measured using an Abbe refractometer under a sodium lamp (589nm) at 20°C;

[0188] 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, test conditions: 20°C, 1kHz, TN test box, box thickness 7μm;

[0189] K ave :The capacitance-voltage characteristic curve (CV curve) of the liquid crystal material was tested using an LCR meter and an anti-parallel friction cell and calculated. Test conditions: 7μm anti-parallel friction cell, V=0.1-20V,

[0190] Tr: 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 is positive IPS type, and the box thickness is 3.5μm;

[0191] γ1: obtained by testing using the LCM-2 liquid crystal property evaluation system; test conditions: 20°C, 160-260V, test box thickness 20μm;

[0192] LTS (-30℃): The nematic liquid crystal medium is placed in a liquid crystal box and stored at a constant temperature of -30℃. The time recorded when crystal precipitation is observed; for example, "≥240" means that no crystals are precipitated after storage at -30℃ for 240 hours.

[0193] The compounds used in the following examples can be synthesized by known methods or obtained through commercial channels. These synthesis techniques are conventional, and the obtained liquid crystal compositions meet the standards of electronic compounds after testing.

[0194] Liquid crystal compositions are prepared according to the proportions of the liquid crystal compositions in the following examples. The preparation of the liquid crystal compositions is carried out according to conventional methods in the art, such as mixing in a prescribed proportion by heating, ultrasonic waves, suspension, etc.

[0195] Comparative Example 1

[0196] The liquid crystal composition of Comparative Example 1 was prepared according to the compounds and their mass percentages listed in Table 2, and filled between two substrates of a liquid crystal display for performance testing.

[0197] Table 2 Formulation and performance parameter test results of liquid crystal composition

[0198]

[0199] Example 1

[0200] The liquid crystal composition of Example 1 was prepared according to the compounds and their mass percentages listed in Table 3, and filled between two substrates of a liquid crystal display for performance testing.

[0201] Table 3 Formulation and performance parameter test results of liquid crystal composition

[0202]

[0203]

[0204] Example 2

[0205] The liquid crystal composition of Example 2 was prepared according to the compounds and their mass percentages listed in Table 4, and filled between two substrates of a liquid crystal display for performance testing.

[0206] Table 4 Liquid crystal composition formula and performance parameter test results

[0207]

[0208] From the comparison between Examples 1 to 2 and Comparative Example 1, it can be seen that the liquid crystal composition of the present invention has a larger optical anisotropy, a higher clearing point, a larger ratio of perpendicular dielectric to dielectric, a larger dielectric anisotropy, a larger average elastic constant, a higher transmittance and a smaller rotational viscosity while maintaining an appropriate or even longer low-temperature storage time by compounding the compound of Formula I, the compound of Formula II and the compound of Formula III.

[0209] Example 3

[0210] The liquid crystal composition of Example 3 was prepared according to the compounds and their mass percentages listed in Table 5, and filled between two substrates of a liquid crystal display for performance testing.

[0211] Table 5 Formulation and performance parameter test results of liquid crystal composition

[0212]

[0213] Example 4

[0214] The liquid crystal composition of Example 4 was prepared according to the compounds and their mass percentages listed in Table 6, and filled between two substrates of a liquid crystal display for performance testing.

[0215] Table 6 Formulation and performance parameter test results of liquid crystal composition

[0216]

[0217] Example 5

[0218] The liquid crystal composition of Example 5 was prepared according to the compounds and their mass percentages listed in Table 7, and filled between two substrates of a liquid crystal display for performance testing.

[0219] Table 7 Formulation and performance parameter test results of liquid crystal composition

[0220]

[0221] Example 6

[0222] The liquid crystal composition of Example 6 was prepared according to the compounds and their mass percentages listed in Table 8, and filled between two substrates of a liquid crystal display for performance testing.

[0223] Table 8 Formulation and performance parameter test results of liquid crystal composition

[0224]

[0225]

[0226] Example 7

[0227] The liquid crystal composition of Example 7 was prepared according to the compounds and their mass percentages listed in Table 9, and filled between two substrates of a liquid crystal display for performance testing.

[0228] Table 9 Formulation and performance parameter test results of liquid crystal composition

[0229]

[0230] Example 8

[0231] The liquid crystal composition of Example 8 was prepared according to the compounds and their mass percentages listed in Table 10, and filled between two substrates of a liquid crystal display for performance testing.

[0232] Table 10 Formulation and performance parameter test results of liquid crystal composition

[0233]

[0234]

[0235] Example 9

[0236] The liquid crystal composition of Example 9 was prepared according to the compounds listed in Table 11 and their mass percentages, and filled between two substrates of a liquid crystal display for performance testing.

[0237] Table 11 Formulation and performance parameter test results of liquid crystal composition

[0238]

[0239] In summary, the present invention makes the liquid crystal composition have a higher optical anisotropy, Δn of 0.096-0.158, a larger average elastic constant, K, by compounding the compound of formula I containing a cyclohexene structure with the compound of formula II and the compound of formula III, and by designing the end groups and cooperating with the specific content. ave The value is 12.3-13.3, the higher the ratio of vertical dielectric to dielectric, ε ⊥ / Δε ratio is 1-1.12, lower rotational viscosity, γ1 is 40-48, higher transmittance and contrast, Tr reaches 15.6-16.4%, can be stably stored at -30℃ for more than 10 days, has better low-temperature storage stability, accelerates the response speed of liquid crystal materials, and is suitable for fast-response IPS, TN, VA, NFFS and other display modes.

[0240] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate a liquid crystal composition and a liquid crystal display device containing the same, 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: At least two compounds of formula II: At least one compound of formula III: as well as At least one compound of formula M: Wherein, R0, R1 and R2 each independently represent a straight chain or branched chain alkyl group containing 1 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group can be independently replaced by -F or -Cl; R X represents a haloalkyl group containing 1 to 5 carbon atoms or a haloalkoxy group containing 1 to 4 carbon atoms; R3 represents halogen, unsubstituted or halogenated or alkenyl containing 2-8 carbon atoms, halogenated or unsubstituted alkenyloxy containing 2-7 carbon atoms; R M1 and R M2 Each independently represents a straight or branched alkyl group containing 1 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 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 or one or at least two rings with single bonds replaced by double bonds And at most one ring or ring express ring ring and ring Each independently expresses Said One or at least two non-adjacent -CH2- can be replaced by -O-; In one or at least two rings, -CH= may be replaced by -N=, and at most one -H may be replaced by halogen; Y1 represents -H or halogen; X1 represents halogen, haloalkyl containing 1 to 5 carbon atoms, haloalkoxy containing 1 to 5 carbon atoms, haloalkenyl containing 2 to 5 carbon atoms or haloalkenyloxy containing 2 to 5 carbon atoms; 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-; n represents 0 or 1; n M Represents 0, 1, or 2; When n M When it represents 1, the compound of formula M does not contain a terphenyl structure; When n M When it indicates 2, the ring Same or different, Z M2 Same or different; The mass percentage of the compound of formula I in the liquid crystal composition is 1%-30%, the mass percentage of the compound of formula II is 1%-20%, the mass percentage of the compound of formula III is 5.5%-50%, and the mass percentage of the compound of formula M is 20%-70%.

2. The liquid crystal composition according to claim 1, characterized in that: The compound of formula I is selected from the group consisting of: as well as 3. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises at least one compound selected from the group consisting of: as well as Wherein, R0 represents a straight chain or branched chain alkyl group containing 1 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group can be independently replaced by -F or -Cl; R X ' represents a straight or branched chain alkyl group containing 1 to 12 carbon atoms.

4. The liquid crystal composition according to claim 1, characterized in that: The compound of formula II is selected from the group consisting of: as well as 5. The liquid crystal composition according to claim 1, characterized in that: The compound of formula III is selected from the group consisting of: as well as 6. The liquid crystal composition according to claim 1, characterized in that: The mass percentage of the compound of formula I in the liquid crystal composition is 1%-12%.

7. The liquid crystal composition according to claim 1, characterized in that: The mass percentage of the compound of formula II in the liquid crystal composition is 4%-12%.

8. The liquid crystal composition according to claim 1, characterized in that: The mass percentage of the compound of formula III in the liquid crystal composition is 5.5%-40%.

9. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises at least one compound selected from the group consisting of compounds of Formula A-1 and Formula A-2: Among them, R A1 and R A2 Each independently represents a straight or branched alkyl group containing 1 to 12 carbon atoms, One or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group can be independently replaced by -F or -Cl; ring and ring Each independently expresses Said One or at least two non-adjacent -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; -CH= in one or at least two rings may be replaced by -N=; one or at least two -H in the aforementioned groups may be replaced by -F or -Cl; ring and ring Each independently expresses Said One or at least two non-adjacent -CH2- can be replaced by -O-; -CH= in one or at least two rings may be replaced by -N=; one or at least two -H in the aforementioned groups may be replaced by -F or -Cl; Z A11 , Z A21 and Z A22 Each independently represents a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -C≡C-, -CH=CH-, -CF=CF-, -CH2O- or -OCH2-; L A11 , L A12 , L A13 , L A21 and L A22 Each independently represents -H, halogen, unsubstituted or halogenated straight-chain alkyl containing 1 to 3 carbon atoms; X A1 and X A2 Each independently represents halogen, 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 and n A2 Each independently represents 0, 1, 2 or 3; when n A11 Represents 2, n A12 Represents 1, Z A11 When all are single bonds, the ring Not for ring Same or different, Z A11 Same or different; when n A11 Indicates 3 o'clock, ring Same or different, Z A11 Same or different; when n A2 When it means 2 or 3, the ring Same or different, Z A21 Same or different; n A12 Indicates 1 or 2; when n A12 When it indicates 2, the ring Same or different.

10. The liquid crystal composition according to claim 9, characterized in that: The compound of formula A-1 is selected from the group consisting of the following compounds: as well as Among them, R A1 represents a straight or branched alkyl group containing 1 to 8 carbon atoms; one or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group may be independently replaced by -F or -Cl; R v and R w Each independently represents -CH2- or -O-; 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; X A1 represents -F, -CF3 or -OCF3; v and w each independently represent 0 or 1.

11. The liquid crystal composition according to claim 9, characterized in that: The compound of formula A-2 is selected from the group consisting of the following compounds: as well as Among them, R A2 represents a straight or branched alkyl group containing 1 to 8 carbon atoms; one or at least two non-adjacent -CH2- in the straight or branched alkyl group containing 1 to 8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; one or at least two -H in the aforementioned group may be independently replaced by -F or -Cl; L A21 , L A22 , L A23 , L A24 and L A25 Each independently represents -H or -F; X A2 It represents -F, -CF3, -OCF3 or -(CH2)2-CH=CF2.

12. The liquid crystal composition according to claim 9, characterized in that: The mass percentage of the compound selected from the group consisting of the compounds of Formula A-1 and Formula A-2 in the liquid crystal composition is 0.1%-60%.

13. The liquid crystal composition according to claim 9, characterized in that: The mass percentage of the compound of formula A-1 in the liquid crystal composition is 0.1%-50%.

14. The liquid crystal composition according to claim 9, characterized in that: The mass percentage of the compound of formula A-2 in the liquid crystal composition is 0.1%-50%.

15. The liquid crystal composition according to claim 1, characterized in that: The compound of formula M is selected from the group consisting of the following compounds: as well as 16. 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 15.

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