Negative dielectric anisotropy liquid crystal composition and liquid crystal display device

Abstract

The present invention relates to a negative dielectric anisotropy liquid crystal composition and a liquid crystal display device. The liquid crystal composition of the present invention comprises: at least one compound represented by formula I; at least one compound represented by formula II. Compared with the prior art, the liquid crystal composition of the present invention has a reduced G1 / K ratio while maintaining a suitable optical anisotropy value and dielectric anisotropy. 11 or G1 / K 33 The value thus has a faster response time and a high VHR after UV light irradiation, thereby being able to obtain the display advantage of improved optical performance, which is beneficial to avoiding / reducing the occurrence of display afterimage phenomenon.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal materials, and more specifically to a liquid crystal composition and a liquid crystal display device. Background Art

[0002] With the development of technology and the progress of the times, the application fields of liquid crystal mixtures have gradually extended to displays for portable computers and desktops, navigation systems and video applications. These application fields have increasingly higher requirements for the performance of liquid crystal mixtures.

[0003] The spatial arrangement of molecules in liquid crystals has an important influence on liquid crystal displays. Among them, the dielectric constant ε of the liquid crystal medium has different values ​​in the direction parallel to the capacitor and perpendicular to the capacitor. The situation where the dielectric constant is greater when the longitudinal axis of the molecule is perpendicular to the capacitor plate than when it is parallel is called dielectric positivity. In other words, if the dielectric constant ε parallel to the longitudinal axis of the molecule is || Greater than the dielectric constant ε perpendicular to the molecular longitudinal axis ⊥ , then the dielectric anisotropy Δε=ε || -ε ⊥ Greater than 0. Most of the liquid crystal media used in conventional displays are dielectrically positive media. Compared with this, Δε=ε || -ε ⊥ A liquid crystal medium with a dielectric anisotropy less than 0 is referred to as a liquid crystal medium with negative dielectric anisotropy.

[0004] With the development of technology, it was found that, for example, in the display mode of VA-TFT ("vertical alignment"), the viewing angle dependence can be improved by negatively adopting a liquid crystal medium with negative dielectric anisotropy. Therefore, liquid crystal media with negative dielectric anisotropy have been widely studied, and it is expected that such liquid crystal media have a fast response time and less afterimages. However, the improvement of the fast response time often leads to an increase in the afterimages of the liquid crystal medium, especially the increase in afterimages after light exposure, thereby affecting its stability. Therefore, how to achieve a negative dielectric anisotropy liquid crystal composition with a fast response time and improved afterimage defects after light exposure, thereby improving stability, is one of the problems to be solved in the art. Summary of the invention

[0005] After in-depth research, the inventors found that by using a negative dielectric anisotropy liquid crystal composition containing a combination of a compound represented by Formula I and a compound represented by Formula II, a reduced G1 / K can be obtained while maintaining a suitable optical anisotropy value and dielectric anisotropy. 11 or G1 / K 33 The value thus has a fast response time and an improved VHR after UV light irradiation, thereby avoiding / reducing the occurrence of display afterimage phenomenon, and achieving display advantages of reduced power consumption and improved stability.

[0006] The present invention includes the following technical solutions.

[0007] In one aspect, the present invention provides a negative dielectric anisotropy liquid crystal composition, the liquid crystal composition comprising:

[0008] At least one compound of formula I; and

[0009] At least one compound of formula II;

[0010]

[0011] Wherein, in Formula I, R1 and R2 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; R1 and R2 are not simultaneously an alkyl group having 1 to 5 carbon atoms, and H on any carbon atom in R1 and R2 is each independently optionally substituted by F;

[0012] In formula II, R3 and R4 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; and H on any carbon atom in R3 and R4 each independently optionally is substituted by F;

[0013] X1, X2, and X3 each independently represent H, -F, -CF3, or -OCF3, and X1, X2, and X3 are not H at the same time.

[0014] In another aspect, the present invention provides a liquid crystal display device, comprising the negative dielectric anisotropy liquid crystal composition of the present invention; the liquid crystal display device is an active matrix display device or a passive matrix display device.

[0015] Effects of the Invention

[0016] Compared with the prior art, the negative dielectric anisotropy liquid crystal composition of the present invention can obtain a reduced G1 / K while maintaining a suitable optical anisotropy value and dielectric anisotropy. 11 or G1 / K 33 The ratio has a fast response time and an improved VHR after UV light irradiation, thereby avoiding / reducing the occurrence of display afterimage phenomenon and achieving display advantages of reduced power consumption and improved stability. DETAILED DESCRIPTION

[0017] [Liquid crystal composition]

[0018] The negative dielectric anisotropy liquid crystal composition of the present invention comprises:

[0019] At least one compound of formula I; and

[0020] At least one compound of formula II;

[0021]

[0022] Wherein, in Formula I, R1 and R2 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; R1 and R2 are not simultaneously an alkyl group having 1 to 5 carbon atoms, and H on any carbon atom in R1 and R2 is each independently optionally substituted by F;

[0023] In formula II, R3 and R4 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; and H on any carbon atom in R3 and R4 each independently may be optionally substituted by F;

[0024] X1, X2, and X3 each independently represent H, -F, -CF3, or -OCF3, and X1, X2, and X3 are not H at the same time.

[0025] For liquid crystal media, the response time of the liquid crystal medium is related to G1 / K according to different display modes. 11 or G1 / K 33 In VA (vertical alignment) or PS-VA (Polymer stabilized vertical alignment) mode, the response time of the liquid crystal medium is related to G1 / K 33 In the FFS (Fringe Field Switching), IPS (In-Plane Switching), PS-FFS (Polymer stabilized Fringe Field Switching), PS-IPS (Polymer stabilized In-Plane Switching) modes, the response time of the liquid crystal medium is related to G1 / K 11 Related.

[0026] The negative dielectric anisotropy liquid crystal composition of the present invention can obtain a reduced G1 / K while maintaining a suitable optical anisotropy value and dielectric anisotropy by containing a combination of the compound represented by the aforementioned formula I and the compound represented by the formula II. 11 or G1 / K 33 The ratio has a fast response time and an improved VHR after UV light irradiation, thereby avoiding / reducing the occurrence of display afterimage phenomenon and achieving display advantages of reduced power consumption and improved stability.

[0027] In the above formula I, the "alkyl group having 1 to 5 carbon atoms" represented by R1 and R2 independently of each other may be a straight-chain alkyl group, a branched-chain alkyl group or a cyclic alkyl group, preferably a straight-chain alkyl group. Examples of such straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl and n-pentyl.

[0028] In the aforementioned formula I, the “alkenyl group having 2 to 5 carbon atoms” represented by the aforementioned R1 and R2 each independently includes, for example, vinyl, propenyl, butenyl, 2-methylpropenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl and the like.

[0029] The hydrogen on any carbon atom in the aforementioned R1 and R2 is optionally replaced by fluorine, which means that the hydrogen on the carbon atom in the alkyl group having 1 to 5 carbon atoms or the alkenyl group having 2 to 5 carbon atoms represented by R1 and R2 is optionally replaced by fluorine, which may be monofluorine substitution, polyfluorine substitution, or perfluorine substitution.

[0030] From having reduced G1 / K 11 or G1 / K 33 From the perspective of having a faster response time and a high VHR after UV light irradiation, thereby being able to obtain the display advantage of improved optical performance, preferably, the compound represented by the aforementioned formula I is selected from the group consisting of the compounds represented by the following formulas I-1 to I-105.

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044] In the aforementioned formula II, the "alkyl group having 1 to 5 carbon atoms" represented by R3 and R4 independently of each other may be a straight-chain alkyl group, a branched-chain alkyl group or a cyclic alkyl group, preferably a straight-chain alkyl group. Examples of such straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl and n-pentyl.

[0045] Examples of the “alkenyl group having 2 to 5 carbon atoms” represented by R3 and R4 independently of each other include ethenyl, propenyl, butenyl, 2-methylpropenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl and 2-methyl-2-butenyl.

[0046] The hydrogen on any carbon atom in the aforementioned R3 and R4 is optionally replaced by fluorine, which means that the hydrogen on the carbon atom in the alkyl group with 1 to 5 carbon atoms or the alkenyl group with 2 to 5 carbon atoms represented by R3 and R4 are optionally replaced by fluorine, which may be monofluorine substitution, polyfluorine substitution, or perfluorine substitution.

[0047] From having reduced G1 / K 11 or G1 / K 33 From the perspective of having a faster response time and a high VHR after UV light irradiation, thereby being able to obtain the display advantage of improved optical performance, preferably, the compound represented by the aforementioned formula II is selected from the group consisting of compounds represented by the following formulas II-1 to II-60, wherein the definitions of R3 and R4 are the same as described above.

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] In certain embodiments, the negative dielectric anisotropy liquid crystal composition of the present invention may further include one or more compounds represented by the following formulae III-1 to III-8:

[0057]

[0058] R5 and R6 each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; hydrogen on any carbon atom in R5 and R6 each independently may be optionally substituted with fluorine;

[0059] (F) represents F or H.

[0060] The "alkyl group having 1 to 5 carbon atoms" independently represented by R5 and R6 may be a linear alkyl group, a branched alkyl group or a cyclic alkyl group, preferably a linear alkyl group. Examples of such a linear alkyl group include methyl, ethyl, n-propyl, n-butyl and n-pentyl.

[0061] Examples of the "alkoxy group having 1 to 5 carbon atoms" independently represented by R5 and R6 include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentyloxy and tert-pentyloxy.

[0062] Examples of the “alkenyl group having 2 to 5 carbon atoms” represented by R5 and R6 above and independently of one another include ethenyl, propenyl, butenyl, 2-methylpropenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl and 2-methyl-2-butenyl.

[0063] Examples of the “alkenyloxy group having 2 to 5 carbon atoms” represented by R5 and R6 above and each independently thereof include vinyloxy, propenyloxy, butenyloxy, 2-methylpropenyloxy, 1-pentenyloxy, 2-pentenyloxy, 2-methyl-1-butenyloxy, 3-methyl-1-butenyloxy and 2-methyl-2-butenyloxy.

[0064] The hydrogen on any carbon atom in R5 and R6 is optionally substituted with fluorine independently of each other, which means that the hydrogen on the carbon atom in the aforementioned alkyl group having 1 to 5 carbon atoms, alkoxy group having 1 to 5 carbon atoms, alkenyl group having 2 to 5 carbon atoms, or alkenyloxy group having 2 to 5 carbon atoms is optionally substituted with fluorine, and it may be monofluorine substitution, polyfluorine substitution, or perfluorine substitution.

[0065] In some embodiments, the negative dielectric anisotropy liquid crystal composition of the present invention may further include one or more compounds represented by the following formula IV:

[0066]

[0067] R7 and R8 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; and H on any carbon atom in R7 and R8 each independently may be optionally substituted by F;

[0068] a and b each independently represent 0, 1 or 2;

[0069] Z1 represents a single bond, -CH2O- or -OCH2-;

[0070] Y represents -F, -CF3 or -OCF3;

[0071] Each independently selected from the group consisting of the following groups:

[0072]

[0073] The "alkyl group having 1 to 5 carbon atoms" independently represented by R7 and R8 may be a straight-chain alkyl group, a branched alkyl group or a cyclic alkyl group. Examples of such straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl and n-pentyl. Examples of such cyclic alkyl groups include cyclopropyl, cyclopropylmethyl, cyclobutyl and cyclopentyl groups shown in the following structural formula.

[0074]

[0075] Examples of the “alkenyl group having 2 to 5 carbon atoms” represented by R7 and R8 above and independently of one another include ethenyl, propenyl, butenyl, 2-methylpropenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl and 2-methyl-2-butenyl.

[0076] The hydrogen on any carbon atom in R7 and R8 is optionally substituted with fluorine independently of each other, which means that the hydrogen on the carbon atom in the aforementioned alkyl group having 1 to 5 carbon atoms or the alkenyl group having 2 to 5 carbon atoms is optionally substituted with fluorine, which may be monofluorine substitution, polyfluorine substitution, or perfluorine substitution.

[0077] Preferably, the compound represented by the aforementioned formula IV is selected from the group consisting of compounds represented by the following formulae IV-1 to IV-40, wherein the definitions of R7 and R8 are the same as described above.

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] R7 and R8 are as defined above, and (F) represents F or H.

[0085] In some embodiments, the negative dielectric anisotropy liquid crystal composition optionally further comprises one or more compounds represented by the following formula V:

[0086]

[0087] R9, R 10 Each independently represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; R9, R 10 H on any carbon atom in is independently optionally substituted by F;

[0088] c and d each independently represent 0 or 1;

[0089] Z2 and Z3 represent a single bond, -CH2O- or -OCH2-;

[0090] W means O or S;

[0091] Each independently selected from the group consisting of the following groups:

[0092]

[0093] As the aforementioned R9, R 10 The "alkyl group having 1 to 5 carbon atoms" represented independently of each other may be a straight-chain alkyl group, a branched alkyl group or a cyclic alkyl group, preferably a straight-chain alkyl group. Examples of such straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl and n-pentyl. Examples of such cyclic groups include cyclopropyl, cyclopropylmethyl, cyclobutyl and cyclopentyl groups shown in the following structural formula.

[0094]

[0095] As the aforementioned R9, R 10 Examples of the "alkenyl group having 2 to 5 carbon atoms" independently include ethenyl, propenyl, butenyl, 2-methylpropenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1-butenyl and 2-methyl-2-butenyl.

[0096] Preferably, the compound represented by the aforementioned formula V is selected from the group consisting of the compounds represented by the following formulas V-1 to V-40, wherein R9, R 10 The definition of is the same as above,

[0097]

[0098]

[0099] In some embodiments, the negative dielectric anisotropy liquid crystal composition optionally further comprises one or more compounds represented by the following formulae VI-1 to VI-10:

[0100]

[0101]

[0102] Regarding the composition of the components in the negative dielectric anisotropic liquid crystal composition of the present invention, in some embodiments, for example, the ratio can be as follows: relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, and the compound represented by formula II is 1 to 60 parts by mass.

[0103] In some other embodiments of the negative dielectric anisotropic liquid crystal composition, the composition of each component can be, for example, the following ratio: relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, and the compound represented by formula III is 1 to 60 parts by mass.

[0104] In some other embodiments of the negative dielectric anisotropic liquid crystal composition, the composition of each component can be, for example, the following ratio: relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, the compound represented by formula III is 1 to 60 parts by mass, and the compound represented by formula IV is 1 to 40 parts by mass.

[0105] In some other embodiments of the negative dielectric anisotropic liquid crystal composition, the composition of each component can be, for example, the following ratio: relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, the compound represented by formula III is 1 to 60 parts by mass, the compound represented by formula IV is 1 to 40 parts by mass, and the compound represented by formula V is 1 to 40 parts by mass.

[0106] In other embodiments of the negative dielectric anisotropic liquid crystal composition, the composition of each component can be, for example, the following ratio: relative to a total of 100 parts by mass of the compounds of Formulas I to V, the compound represented by Formula I is 1 to 40 parts by mass, the compound represented by Formula II is 1 to 60 parts by mass, the compound represented by Formula III is 1 to 60 parts by mass, the compound represented by Formula IV is 1 to 40 parts by mass, the compound represented by Formula V is 1 to 40 parts by mass, and the compound represented by Formula VI is 0.1 to 5 parts by mass.

[0107] In the negative dielectric anisotropy liquid crystal composition of the present invention, in addition to the liquid crystal compounds listed above, those skilled in the art may also add other liquid crystal compounds without destroying the desired performance of the liquid crystal composition.

[0108] The negative dielectric anisotropy liquid crystal composition of the present invention may optionally further include dopants with various functions, such as antioxidants, ultraviolet absorbers, and chiral agents.

[0109] [Liquid crystal display device]

[0110] The second aspect of the present invention provides a liquid crystal display device, which is not particularly limited as long as it contains any of the liquid crystal compositions described above. The liquid crystal display device of the present invention can be an active matrix display device or a passive matrix display device. Those skilled in the art can select a suitable liquid crystal display component and a structure of a liquid crystal display according to the required performance.

[0111] Example

[0112] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0113] In the present invention, the preparation methods are conventional methods unless otherwise specified, the raw materials used are all available from public commercial channels unless otherwise specified, the percentages are by mass, the temperatures are in degrees Celsius (°C), and the liquid crystal compounds are also liquid crystal monomers.

[0114] [Negative dielectric anisotropy liquid crystal composition]

[0115] In Examples 1 to 9 and Comparative Examples 1 and 2, negative dielectric anisotropic liquid crystal compositions of different compositions were prepared, wherein the monomer structure, dosage (parts by mass) of the specific compounds used in each example, and the test results of the performance parameters of the obtained liquid crystal media are shown in Tables 1 to 11 below, respectively.

[0116] The temperature unit in each embodiment is °C, and the specific meanings of other symbols and test conditions are as follows:

[0117] Gamma1 (mPa.s) represents the rotational viscosity coefficient of the liquid crystal compound, and the determination method is as follows: instrument INSTEC: ALCT-IR1, test box thickness 18 micron vertical box, temperature 25°C, abbreviated as "G1";

[0118] K 11 is the torsional elastic constant, K 33 is the splay elastic constant, the test conditions are: 25°C, INSTEC:ALCT-IR1, 18 μm vertical box;

[0119] Δε represents dielectric anisotropy, 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: 25°C, INSTEC:ALCT-IR1, 18 μm vertical box;

[0120] Δn represents optical anisotropy, Δn = n e -n o , where n o is the refractive index of ordinary light, n e It is the refractive index of extraordinary light, and the test conditions are: 589nm, 25±0.2℃.

[0121] VHR stands for voltage holding ratio (%) after UV irradiation. The test conditions are 20±2℃, voltage ±5V, pulse width 10ms, and voltage holding time 16.7ms. The test equipment is TOYO Model 6254 Liquid Crystal Performance Comprehensive Tester. VHR test uses UV polymerization of polymerizable compounds with a wavelength of 313nm and an irradiation intensity of 0.5Mw / cm 2 The ultraviolet light was used for light irradiation, and the irradiation time was 2 minutes.

[0122] In the present invention, the preparation method of the negative dielectric anisotropy liquid crystal composition is as follows: each liquid crystal monomer is weighed according to a certain ratio and put into a stainless steel beaker, the stainless steel beaker containing each liquid crystal monomer is placed on a magnetic stirring device to heat and melt, after most of the liquid crystal monomers in the stainless steel beaker are melted, a magnetic rotor is added to the stainless steel beaker, the mixture is stirred evenly, and the liquid crystal composition is obtained after cooling to room temperature.

[0123] The obtained liquid crystal composition is filled between two substrates of a liquid crystal display for performance testing.

[0124] The structure of the liquid crystal monomer used in the examples of the present invention is represented by the following codes, and the code representation method of the liquid crystal ring structure, end group, and connecting group is shown in the following Table (I) and Table (II).

[0125] Table (I): Corresponding codes of ring structures

[0126]

[0127]

[0128] Table (II): Corresponding codes of terminal groups and linking groups

[0129]

[0130]

[0131] Example:

[0132]

[0133]

[0134] The liquid crystal compositions of Examples 1 to 8 are obtained by combining the compounds represented by the aforementioned Formula I, Formula II, etc. with other ingredients. The compositions and contents of the components in the liquid crystal compositions of Examples 1 to 8 are shown in the following Tables 1 to 8.

[0135] Table 1 Component ratio and performance parameters of the liquid crystal medium of Example 1

[0136]

[0137] Table 2 Component ratio and performance parameters of the liquid crystal medium of Example 2

[0138]

[0139] Table 3 Component ratio and performance parameters of the liquid crystal medium of Example 3

[0140]

[0141] Table 4 Component ratio and performance parameters of the liquid crystal medium of Example 4

[0142]

[0143] Table 5 Component ratio and performance parameters of the liquid crystal medium of Example 5

[0144]

[0145] Table 6 Component ratio and performance parameters of the liquid crystal medium of Example 6

[0146]

[0147] Table 7 Component ratio and performance parameters of the liquid crystal medium of Example 7

[0148]

[0149] Table 8 Component ratios and performance parameters of the liquid crystal medium of Example 8

[0150]

[0151] The formulations of Comparative Examples 1 and 2 are shown in Tables 9 and 10 below.

[0152] Table 9 Component ratio and performance parameters of the liquid crystal medium of comparative example 1

[0153]

[0154] Table 10 Component ratio and performance parameters of the liquid crystal medium of comparative example 2

[0155]

[0156] By comparing the embodiments with the comparative examples, it can be found that compared with the comparative examples 1 and 2 which do not contain the combination of formula I and formula II, the embodiments containing the combination of formula I and formula II can have a reduced G1 / K while maintaining a suitable optical anisotropy value and dielectric anisotropy performance. 11 or G1 / K 33 The value thus has a fast response time and also obtains an improved VHR value, thereby being able to obtain the display advantages of reduced power consumption and improved stability, which is beneficial to avoid / reduce the occurrence of display afterimage phenomenon.

[0157] Although the present invention does not exhaust all liquid crystal mixtures claimed for protection, it is foreseeable that, based on the above disclosed embodiments, those skilled in the art can obtain other similar liquid crystal materials in a similar manner by combining their own professional attempts without creative work. Due to limited space, only representative implementations are listed here.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A negative dielectric anisotropy liquid crystal composition, characterized in that: The liquid crystal composition comprises: At least one compound of formula I; and At least one compound of formula II; Wherein, in Formula I, R1 and R2 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; R1 and R2 are not simultaneously an alkyl group having 1 to 5 carbon atoms, and H on any carbon atom in R1 and R2 is each independently optionally substituted by F; In formula II, R3 and R4 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; and H on any carbon atom in R3 and R4 each independently optionally is substituted by F; X1, X2, and X3 each independently represent H, -F, -CF3, or -OCF3, and X1, X2, and X3 are not H at the same time; Relative to 100 parts by mass of the negative dielectric anisotropy liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, and the compound represented by formula II is 1 to 60 parts by mass.

2. The negative dielectric anisotropy liquid crystal composition according to claim 1, characterized in that: The compound represented by formula I is selected from the group consisting of compounds represented by formulas I-1 to I-105 below:

3. The negative dielectric anisotropy liquid crystal composition according to claim 1, characterized in that: The compound represented by formula II is selected from the group consisting of compounds represented by formula II-1 to II-60 below: R3 and R4 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; H on any carbon atom in R3 and R4 each independently may be optionally substituted by F.

4. The negative dielectric anisotropy liquid crystal composition according to any one of claims 1 to 3, characterized in that: The liquid crystal composition further comprises one or more compounds represented by the following formulae III-1 to III-7: R5 and R6 each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms; hydrogen on any carbon atom in R5 and R6 each independently may be optionally substituted with fluorine; (F) represents F or H.

5. The negative dielectric anisotropy liquid crystal composition according to claim 4, characterized in that: The liquid crystal composition further comprises one or more compounds represented by the following formula IV: R7 and R8 each independently represent an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; and H on any carbon atom in R7 and R8 each independently may be optionally substituted by F; a and b each independently represent 0, 1 or 2; Z1 represents a single bond, -CH2O- or -OCH2-; Y represents -F, -CF3 or -OCF3; Each independently selected from the group consisting of the following groups:

6. The negative dielectric anisotropy liquid crystal composition according to claim 5, characterized in that: The compound represented by formula IV is selected from the group consisting of compounds represented by formulas IV-1 to IV-40 below, wherein R7 and R8 have the same definitions as those in claim 5, (F) represents F or H.

7. The negative dielectric anisotropy liquid crystal composition according to claim 5, characterized in that: The liquid crystal composition further comprises one or more compounds represented by the following formula V: R9, R 10 Each independently represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms; R9, R 10 H on any carbon atom in is independently optionally substituted by F; c and d each independently represent 0 or 1; Z2 and Z3 represent a single bond, -CH2O- or -OCH2-; W means O or S; Each independently selected from the group consisting of the following groups:

8. The negative dielectric anisotropy liquid crystal composition according to claim 7, characterized in that: The compound represented by formula V is selected from the group consisting of compounds represented by formulas V-1 to V-12 below, wherein R9, R 10 has the same meaning as in claim 7, 9. The negative dielectric anisotropy liquid crystal composition according to claim 7, characterized in that: The liquid crystal composition further comprises one or more compounds represented by the following formulas VI-1 to VI-10:

10. The negative dielectric anisotropy liquid crystal composition according to claim 4, characterized in that: Relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, and the compounds represented by formulas III-1 to III-7 are 1 to 60 parts by mass.

11. The negative dielectric anisotropy liquid crystal composition according to claim 5, characterized in that: Relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, the compounds represented by formulas III-1 to III-7 are 1 to 60 parts by mass, and the compound represented by formula IV is 1 to 40 parts by mass.

12. The negative dielectric anisotropy liquid crystal composition according to claim 7, characterized in that: Relative to 100 parts by mass of the negative dielectric anisotropic liquid crystal composition, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, the compound represented by formulas III-1 to III-7 is 1 to 60 parts by mass, the compound represented by formula IV is 1 to 40 parts by mass, and the compound represented by formula V is 1 to 40 parts by mass.

13. The negative dielectric anisotropy liquid crystal composition according to claim 9, characterized in that: Relative to a total of 100 parts by mass of the compounds represented by formulas I to V, the compound represented by formula I is 1 to 40 parts by mass, the compound represented by formula II is 1 to 60 parts by mass, the compounds represented by formulas III-1 to III-7 are 1 to 60 parts by mass, the compound represented by formula IV is 1 to 40 parts by mass, the compound represented by formula V is 1 to 40 parts by mass, and the compounds represented by formulas VI-1 to VI-10 are 0.1 to 5 parts by mass.

14. 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 13; the liquid crystal display device is an active matrix display device or a passive matrix display device.

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