TW201942341A - Liquid crystal composition and liquid crystal display device - Google Patents

Abstract

The present application provides a liquid crystal composition and a liquid crystal display device. The liquid crystal composition comprises at least one compound of general formula I, at least one compound of general formula II and at least one compound of general formula III. By compounding the three compounds, the composition can have better optical anisotropy and dielectric anisotropy, good low-temperature intersolubility, excellent resistivity, and excellent voltage retention after ultraviolet irradiation.

Description

Liquid crystal composition and liquid crystal display device

The invention belongs to the technical field of liquid crystal materials, and relates to a liquid crystal composition and a liquid crystal display device.

Liquid crystal display elements are used in home appliances, computers, mobile phones, electronic dictionaries, and other fields, including clocks, electronic calculators, and display screens. As a liquid crystal display method, its representative methods are TN (twisted nematic) type, STN (super twisted nematic) type, DS (dynamic light scattering) type, GH (guest-host) type, IPS (in-plane switching) type, OCB (optically compensated birefringence) type, ECB (voltage controlled birefringence) type, VA (vertical alignment) type, CSH (color super vertical) type, FLS (ferroelectric liquid crystal) type, or PSA (polymer stable alignment) Type and so on. It is divided into PM (passive matrix) type and AM (active matrix) type according to the driving method of the element. PM is divided into static and multi-channel types. AM is divided into TFT (thin film transistor), MIM (metal-insulating layer-metal) and other types. Regardless of the display mode, the liquid crystal materials used must have low driving voltage, high response speed, wide operating temperature range, large absolute value of dielectric anisotropy, high phase transition temperature, and good mutual solubility.

However, in the prior art, it is difficult to obtain a liquid crystal composition having a large absolute value of negative dielectric anisotropy, good low-temperature stability, and quick response. A liquid crystal composition having a large absolute value of dielectric anisotropy has a high critical voltage, high power consumption, and relatively slow response speed. Therefore, in order to meet the increasing demand for applications, the memory in the art is continuously improving the liquid crystal compounds with negative dielectric anisotropy.

In addition, with the development of the liquid crystal display field, the thickness of liquid crystal panels is getting thinner and thinner, and higher requirements have been put forward for the display effect of liquid crystal display elements. Moreover, liquid crystal displays will experience visible UV radiation, High temperature and long-term addressing drive, many liquid crystal media can not solve the problem of display quality well, resulting in the deterioration of the yield of liquid crystal display elements. Among them, image sticking is one of the representative of quality problems of liquid crystal display elements.

The image sticking is in the same screen. Because the liquid crystal is polarized due to long-term driving, the liquid crystal deflection is not controlled by the signal voltage, so that the same screen is displayed on the screen for a period of time, and this phenomenon also changes over time Weakened and finally disappeared. The image residue is divided into line residue and surface residue. Among them, the line residue has a great relationship with the reliability of the liquid crystal material itself. The performance parameter commonly used to characterize the reliability of the liquid crystal material is the voltage retention rate VHR. The higher the VHR, the liquid crystal material The lower the possibility of being affected by interference factors (such as liquid crystal impurities, high and low temperature, UV radiation, etc.).

However, the current liquid crystal media cannot meet the above requirements at the same time. For example, the liquid crystal compositions disclosed in Japanese Patent Application Laid-Open No. 9-124529 and Japanese Patent Application Laid-Open No. 2006-169472 include thermally stable antioxidants, but they are resistant to light. 2. The thermal stability is still poor and cannot meet the requirements.

Therefore, how to develop a liquid crystal composition that can ensure suitable optical anisotropy and dielectric anisotropy, and also has a relatively high voltage retention rate VHR, thereby improving the display quality of a liquid crystal display device is in the art. Research focus.

In view of the problems of the prior art, the object of the present invention is to provide a liquid crystal composition and a liquid crystal display device. The liquid crystal composition of the present invention has suitable optical anisotropy, dielectric anisotropy, and good low-temperature mutual solubility and voltage. Retention rate.

To achieve this, the present invention adopts the following technical solutions:

In one aspect, the present invention provides a liquid crystal composition comprising at least one compound of general formula I, at least one compound of general formula II, and at least one compound of general formula III:
;
Wherein R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a straight or branched chain alkyl or alkoxy group containing 1-12 carbon atoms, and a straight chain containing 2-12 carbon atoms Or a branched chain alkenyl or alkenyloxy group, a cycloalkyl group having 3 to 12 carbon atoms, or a straight or branched chain alkyl or alkoxy group having 1 to 12 carbon atoms One or two non-adjacent -CH ₂ -groups in a straight or branched chain alkenyl or alkenyloxy group containing 2-12 carbon atoms, or a cycloalkyl group containing 3-12 carbon atoms Oxygen atoms are not directly adjacent to each other by -O-, -CH = CH-, -CO-, -OCO-, or -COO- groups; R ₆ is a straight group containing 1-12 carbon atoms. Chain or branched alkyl; ring with Each independently , or ; N ₁ is 1 or 2; n ₂ is 0 or 1; m ₁ and m _{2 are} independently 0 or 1.

In the present invention, since the liquid crystal composition contains compounds of the general formula I, II and III at the same time, the components cooperate with each other to make the composition have higher optical anisotropy, dielectric anisotropy, and good low-temperature mutual solubility. , And excellent voltage retention, can better solve the problem of image retention.

Preferably, the compound of the general formula I accounts for 1-60% of the total weight of the liquid crystal composition, such as 1%, 2%, 4%, 6%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, preferably 5-50%, more preferably 10-45%; the compound of the general formula III accounts for 1- 1 of the total weight of the liquid crystal composition 20%, such as 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, or 20%. If the content of the compound of the general formula III is higher than 20%, the mutual solubility of the liquid crystal composition is deteriorated.

Preferably, the compound of the general formula II accounts for more than 10% of the total weight of the liquid crystal composition, such as 10%, 12%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, or 30%. %, Preferably 10-30%, further preferably 13-30%, and still more preferably 15-30%. If the content of the compound of the general formula II is less than 10%, the phase transition temperature of the liquid crystal composition is reduced, so that the working scene of the liquid crystal composition is limited.

Preferably, the compound of the general formula I is:
I-1 and / or
I-2, where the definitions of R ₁ and R ₂ are as described above, and are not repeated here.
The compound of the general formula II is any one or a combination of at least two of the compounds having the following structure:
II-1;
II-2;
II-3;
II-4;
II-5;
II-6;
II-7; the definitions of R ₃ and R ₄ are as described above, and are not repeated here.
The compound of the general formula III is any one or a combination of at least two of the compounds having the following structure:
III-1;
III-2;
III-3;
III-4;
III-5;
The definitions of R ₅ and R ₆ are as described above, and are not repeated here.

In the present invention, the straight or branched alkyl or alkoxy group containing 1-12 carbon atoms may be containing 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, A straight or branched alkyl or alkoxy group of 11 or 12 carbon atoms. In the present invention, examples of the straight-chain or branched alkyl group may be methyl, ethyl, propyl, isopropyl, butyl, pentyl, octyl, heptyl, decyl, dodecane Base etc. Examples of the linear or branched alkoxy group may be a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like.

Preferably, the liquid crystal composition according to the present invention further comprises at least one compound of the general formula IV:

Where R ₇ and R ₈ are each independently a straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, a straight or branched alkenyl or alkoxy group containing 2 to 12 carbon atoms Group, a cycloalkyl group having 3 to 12 carbon atoms; or the straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, or a straight or branched chain to 2 to 12 carbon atoms One or two non-adjacent -CH ₂ -groups of alkenyl or alkenyloxy, cycloalkyl groups containing 3-12 carbon atoms are replaced by -O-, -CH in a way that the oxygen atoms are not directly adjacent = CH-, -CO-, -OCO- or -COO- substituted groups, rings for , , or Z ₁ is -CH ₂ CH _2- , -CH ₂ O-, -OCH _2- , -CO-O-, -O-CO- or a single bond, n ₃ is 0, 1 or 2, and a is 0 or 1, when a is 0, n ₃ is 1 and the ring Not for .

Preferably, the compound of the general formula IV accounts for 5-80% of the total weight of the liquid crystal composition, such as 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, more preferably 10-70%, still more preferably 15-60%.

Preferably, the compound of the general formula IV is any one or a combination of at least two of the compounds having the following structure:
IV-1;
IV-2;
IV-3;
IV-4;
IV-5;
IV-6;
IV-7;
IV-8;
IV-9,
The definitions of R ₇ and R ₈ are as described above, and are not repeated here.

Preferably, the liquid crystal composition according to the present invention further comprises at least one compound of the general formula V:
V
Among them, X ₁ and X _{2 are} independently a straight or branched alkyl group containing 1 to 12 carbon atoms, and a straight or branched alkenyl group containing 2 to 12 carbon atoms.

Preferably, the compound of the general formula V accounts for 1-30% of the total weight of the liquid crystal composition, such as 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28% or 30%, preferably 1-20%, and more preferably 1-15%.

Preferably, the liquid crystal composition according to the present invention further comprises at least one compound of the general formula VI:
;
Among them, R ₉ and R ₁₀ are each independently a straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, a straight or branched alkenyl group or alkene containing 2 to 12 carbon atoms Any one of an alkoxy group, a cycloalkyl group having 3 to 12 carbon atoms, or the straight or branched chain alkyl or alkoxy group having 1 to 12 carbon atoms, containing 2 to 12 carbon atoms One or two non-adjacent -CH ₂ -groups in a straight or branched chain alkenyl or alkenyloxy group, or a cycloalkyl group containing 3 to 12 carbon atoms are replaced by oxygen atoms that are not directly adjacent -O-, -CH = CH-, -CO-, -OCO- or -COO- replaced groups; ring for , , , , , , , or ; N ₄ is 1, 2 or 3; Z ₂ is -CH ₂ CH _2- , -CO-O-, -O-CO-, -C≡C- or a single bond.

Preferably, the compound of the general formula VI accounts for 0-60% of the total weight of the liquid crystal composition, such as 0%, 1%, 3%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%, preferably 1-30%, more preferably 1-20%.

Preferably, the compound of the general formula VI is any one or a combination of at least two of the compounds having the following structure:
VI-1;
VI-2;
VI-3;
VI-4;
VI-5;
VI-6;
VI-7;
VI-8;
VI-9;
VI-10;
VI-11;
VI-12;
VI-13,
The definitions of R ₉ and R ₁₀ are as described above, and are not repeated here.

In the present invention, the alkenyl group or alkenyl group containing 2 to 12 carbon atoms may be a straight group containing 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms. Chain or branched alkenyl or alkenyloxy. In the present invention, examples of the linear or branched alkenyl group may be , , , Etc. Examples of the linear or branched alkenyloxy group may be , , Wait.

Preferably, the cycloalkyl group containing 3-12 carbon atoms is a cycloalkyl group having 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms, and specific examples may be cyclopropyl, cyclo Butyl, cyclopentyl, cyclohexyl and the like.

In the present invention, the straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, the straight or branched alkenyl or alkenyl group containing 2 to 12 carbon atoms, containing One or two non-adjacent -CH ₂ -groups in a cycloalkyl group of 3-12 carbon atoms are replaced by -O-, -CH = CH-, -CO-, -OCO- or -COO- group substitution refers to a straight or branched alkyl or alkoxy group containing 1-12 carbon atoms, a straight or branched alkenyl group containing 2-12 carbon atoms Or an alkenyloxy group, a -CH ₂ -group in a cycloalkyl group having 3 to 12 carbon atoms may be replaced by a -O-, -CH = CH-, -CO-, -OCO-, or -COO- group , But cannot be substituted by two adjacent -CH ₂ -groups at the same time, and cannot be substituted in such a way that the oxygen atoms are directly connected, for example, one -CH ₂ -in -OCH ₂ CH ₂ CH ₃ is replaced with -O -That is -CH ₂ OCH ₃ , replacing one -CH ₂ -in -OCH ₂ CH ₂ CH ₃ with -O- is -OCH ₂ OCH ₃ , and not -OOCH ₂ CH ₃ .

Preferably, the liquid crystal composition further comprises at least one polymerizable compound; further preferably, the polymerizable compound is selected from any one or a combination of at least two compounds having a structure represented by the general formula RM:
RM;
Where P ₁ and P ₂ are each independently , , , , , , , , , , , , Or -SH; r ₁ is an integer of 1-3 (for example, 1, 2 or 3); r ₂ and r ₃ are each independently an integer of 0-6 (for example, 0, 1, 2, 3, 4, 5 or 6) ); R ₄ and r ₅ are each independently an integer of 0-4 (for example, 0, 1, 2, 3, or 4); Z is a single bond, -CH ₂ CH _2- , -COO-, -OCO-,- CH ₂ O-, -OCH ₂ -or -CH = CH-COO-; Z _p1 and Z _{p2 are the} same or different and are each independently selected from a single bond, -O-, -S-, -NH-, -NHCOO- , -OCONH-, -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF _2- , -CH ₂ CH _2- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -CF = CH-, -CH = CF-, -CF = CF-, -CO-, -COO-, -OCO-, -OCOO-, -CH _2- , -OCH ₂ -,- SCH _2- , -CH ₂ S-, -CH = CH-, -C≡C-, -CH = CH-COO-, or -OCO-CH = CH-; Y ₁ and Y ₂ are each independently H, halogen , An alkyl or alkoxy group having 1 to 3 C atoms (such as 1, 2 or 3);
Preferably, P ₁ and P ₂ are each independently or ;
Preferably, the compound having the structure represented by the general formula RM is selected from any one or a combination of at least two of the following compounds:
RM-1;
RM-2;
RM-3;
RM-4;
RM-5;
RM-6;
RM-7;
RM-8;
RM-9;
RM-10;
RM-11;
RM-12;
RM-13;
RM-14;
RM-15;
RM-16;
RM-17;
RM-18;
RM-19;
RM-20;
RM-21;
RM-22;
RM-23;
RM-24;
RM-25;
RM-26;
RM-27;
RM-28;
RM-29;
RM-30;
RM-31;
RM-32;
RM-33;
RM-34;
RM-35;
RM-36;
RM-37;
RM-38 ;.

Further preferably, the compound having the structure represented by the general formula RM is selected from RM-1, RM-2, RM-3, RM-4, RM-5, RM-6, RM-7, RM-8, RM Any one of -11, RM-12, RM-13, RM-14, RM-29, RM-30, RM-31, RM-32, RM-33 or RM-34 or a combination of at least two of them.

When the liquid crystal composition of the present invention and the polymerizable compound are polymerized, the formed polymer particles are relatively uniform, and it is difficult to form large polymer particles, and further, no bright spots are formed in the panel to affect the display effect.

The liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, an antioxidant, an ultraviolet absorber, an infrared absorber, a light stabilizer, and the like in addition to the compounds described above.

As additives such as antioxidants and light stabilizers used in the liquid crystal composition of the present invention, the following are preferred:
Preferably, the light stabilizer is selected from the stabilizers shown below:
Where n is a positive integer from 1 to 12, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

In the embodiment of the present invention, preferably, the light stabilizer accounts for 0-5% of the total weight of the liquid crystal composition; for example, 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, more preferably, the light stabilizer accounts for 0-1% of the total weight of the liquid crystal composition; as particularly preferred Preferably, the light stabilizer accounts for 0-0.1% of the total weight of the liquid crystal composition.

In another aspect, the present invention provides a liquid crystal display device including the liquid crystal composition as described above.

Compared with the prior art, the present invention has the following beneficial effects:
(1) The liquid crystal composition of the present invention has suitable optical anisotropy and dielectric anisotropy, and also has good low-temperature mutual solubility and voltage retention rate, which can better solve the problem of image retention;
(2) When the liquid crystal composition of the present invention is polymerized with a polymerizable compound, the polymer particles formed are relatively uniform, it is difficult to form large polymer particles, and further, no bright spots are formed in the panel to affect display effects.

The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are merely to help understand the present invention and should not be regarded as a specific limitation to the present invention.

For ease of expression, in the following examples, the group structure of the liquid crystal composition is represented by the codes listed in Table 1:
Table 1 Structure code of compound group in liquid crystal composition

Take the compound of the following structural formula as an example to explain its structural code:
If the structural formula is expressed by the code shown in Table 1, it can be expressed as nCPPm, where n is the number of carbon atoms of the left alkyl group, for example, n is 3, which means that the alkyl group is -C ₃ H ₇ . C represents cyclohexane, P represents phenyl, and m represents the number of carbon atoms in the right alkyl group. For example, m is 2, which means that the alkyl group is -C ₂ H ₅ .

In the following embodiments, the abbreviated codes of the performance testing projects are shown in Table 2.
Table 2 Abbreviations for performance testing projects
Among them, VHR (initial) was measured using a TOY06254 liquid crystal physical property evaluation system; the test temperature was 65 ° C, the test voltage was 5V, and the test frequency was 6Hz.
VHR (UV) was measured using a TOY06254 liquid crystal physical property evaluation system; the light was irradiated with light having a wavelength of 365 nm and an energy of 6000 mJ / cm ² and tested. The test temperature was 65 ° C, the test voltage was 5 V, and the test frequency was 6 Hz.

Each component used in the liquid crystal composition of the following examples can be synthesized by a known method or can be obtained through commercial means. Each component of the obtained liquid crystal composition is tested to meet the standards of electronic compounds.

The liquid crystal compositions in the following examples are mixed according to the distribution ratio of each group (the parentheses of the components in the parentheses at the end of the examples are the general formula of the components), and are mixed by conventional preparation methods such as heating, ultrasound, suspension, etc. A liquid crystal composition was obtained.

Example 1

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 2

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 3

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 4

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 5

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 6

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 7

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Example 8

In this embodiment, the liquid crystal composition includes components with a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Comparative Example 1

In this comparative example, the liquid crystal composition includes components having a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Comparative Example 2

In this comparative example, the liquid crystal composition includes components having a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Comparative Example 3

In this comparative example, the liquid crystal composition includes components having a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

Comparative Example 4

In this comparative example, the liquid crystal composition includes components having a mass percentage content as shown in the following table, and the performance test results are listed in the following table:

As can be seen from the comparison between Examples 1-3 and Comparative Examples 1-3, the liquid crystal composition of the present invention has good low-temperature mutual solubility while maintaining relatively high clearing point, dielectric anisotropy, and optical anisotropy. And the voltage retention ratio, the problem of image retention can be better solved; it can be seen from the comparison between Example 5 and Comparative Example 4 that the liquid crystal composition of the present invention has improved low-temperature mutual solubility and voltage retention ratio. And optical anisotropy were also significantly improved.

Example 9

In this example, 0.3% of the polymerizable compound RM-13 was added to the liquid crystal compositions of Examples 1-8 and Comparative Examples 1-4, and the liquid crystal compositions of 4 μm were poured into the liquid crystal compositions after they were completely dissolved. In a (VA) box, a voltage of 16 V was applied and irradiated with UV for 180 s, and the polymerization bright spots in the holes were observed using an optical microscope. The results are shown in Table 4.
Table 4
It can be seen from the data in Table 4 that when the liquid crystal composition of the present invention is used in combination with a polymerizable material, the composition of the present invention can make the polymerizable material polymerize uniformly, and it is less prone to the phenomenon of defective bright spots, which improves the display panel of the liquid crystal display device Display effect.

The present invention describes the liquid crystal composition and the liquid crystal display device of the present invention through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must be implemented by relying on the above embodiments. Those skilled in the art should know that any improvement to the present invention, equivalent replacement of the raw materials of the products of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

A liquid crystal composition, characterized in that the liquid crystal composition comprises at least one compound of general formula I, at least one compound of general formula II, and at least one compound of general formula III: ; Wherein R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each independently a straight or branched chain alkyl or alkoxy group containing 1-12 carbon atoms, and a straight group containing 2-12 carbon atoms Any one of a chain or branched alkenyl group or alkenyloxy group, a cycloalkyl group having 3 to 12 carbon atoms; or the straight or branched chain alkyl or alkoxy group having 1 to 12 carbon atoms One or two non-adjacent -CH ₂ -groups in a straight-chain or branched alkenyl or alkenyloxy group containing 2-12 carbon atoms, a cycloalkyl group containing 3-12 carbon atoms Groups in which the oxygen atoms are not directly adjacent to each other are replaced by -O-, -CH = CH-, -CO-, -OCO-, or -COO- groups; R ₆ is a group containing 1-12 carbon atoms Linear or branched alkyl; ring with Each independently , or ; N ₁ is 1 or 2; n ₂ is 0 or 1; m ₁ and m _{2 are} independently 0 or 1. The liquid crystal composition according to item 1 of the scope of patent application, wherein the compound of the general formula I accounts for 1-60%, preferably 5-50%, and more preferably 10-45% of the total weight of the liquid crystal composition; The compound of III constitutes 1-20% of the total weight of the liquid crystal composition. The liquid crystal composition according to item 1 or 2 of the scope of application for a patent, wherein the compound of the general formula II accounts for more than 10%, preferably 10-30%, more preferably 13-30% of the total weight of the liquid crystal composition, and further 15-30% is preferred. The liquid crystal composition according to any one of claims 1 to 3, wherein the compound of the general formula I is: I-1 and / or I-2; The compound of the general formula II is any one or a combination of at least two of the compounds having the following structure: II-1; II-2; II-3; II-4; II-5; II-6; II-7; The compound of the general formula III is any one or a combination of at least two of the compounds having the following structure: III-1; III-2; III-3; III-4; III-5. The liquid crystal composition according to any one of claims 1 to 4, wherein the liquid crystal composition further comprises at least one compound of the general formula IV: Where R ₇ and R ₈ are each independently a straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, a straight or branched alkenyl or alkoxy group containing 2 to 12 carbon atoms Any of a cycloalkyl group containing 3 to 12 carbon atoms; or a straight or branched chain alkyl or alkoxy group containing 1 to 12 carbon atoms; One or two non-adjacent -CH ₂ -groups in a chain or branched alkenyl or alkenyloxy group, or a cycloalkyl group containing 3-12 carbon atoms are replaced by -O in a manner that the oxygen atoms are not directly adjacent. -, -CH = CH-, -CO-, -OCO- or -COO- substituted groups, rings for , , or Z ₁ is -CH ₂ CH _2- , -CH ₂ O-, -OCH _2- , -CO-O-, -O-CO- or a single bond, n ₃ is 0, 1 or 2, and a is 0 or 1, when a is 0, n ₃ is 1 and the ring Not for ; Preferably, the compound of general formula IV accounts for 5-80% of the total weight of the liquid crystal composition, further preferably 10-70%, and still more preferably 15-60%; preferably, the compound of general formula IV has the following structure Any one or a combination of at least two of the compounds: IV-1; IV-2; IV-3; IV-4; IV-5; IV-6; IV-7; IV-8; IV-9. The liquid crystal composition according to any one of claims 1 to 5, wherein the liquid crystal composition further comprises at least one compound of the general formula V: V wherein X ₁ and X _{2 are} independently a straight or branched alkyl group containing 1 to 12 carbon atoms, and a straight or branched alkenyl group containing 2 to 12 carbon atoms; preferably, said The compound of the general formula V accounts for 1-30% of the total weight of the liquid crystal composition, more preferably 1-20%, and still more preferably 1-15%. The liquid crystal composition according to any one of claims 1 to 6, wherein the liquid crystal composition further comprises at least one compound of the general formula VI: Where R ₉ and R ₁₀ are each independently a straight or branched alkyl or alkoxy group containing 1 to 12 carbon atoms, a straight or branched alkenyl group containing 2 to 12 carbon atoms, or Any one of alkenyloxy, cycloalkyl having 3-12 carbon atoms, or the straight-chain or branched alkyl or alkoxy group containing 1-12 carbon atoms, containing 2-12 carbons One or two non-adjacent -CH ₂ -groups of straight or branched chain alkenyl or alkenyloxy groups, cycloalkyl groups containing 3-12 carbon atoms in a way that the oxygen atoms are not directly adjacent A group substituted with -O-, -CH = CH-, -CO-, -OCO-, or -COO-; a ring for , , , , , , , or ; N ₄ is 1, 2 or 3; Z ₂ is -CH ₂ CH _2- , -CO-O-, -O-CO-, -C≡C- or a single bond; preferably, the general formula VI The compound accounts for 0-60%, preferably 1-30%, and more preferably 1-20% of the total weight of the liquid crystal composition. Preferably, the compound of the general formula VI is any one or at least two of the compounds having the following structure The combination: VI-1; VI-2; VI-3; VI-4; VI-5; VI-6; VI-7; VI-8; VI-9; VI-10; VI-11; VI-12; VI-13. The liquid crystal composition according to any one of claims 1 to 7, wherein the liquid crystal composition further comprises at least one polymerizable compound. A liquid crystal display device, characterized in that the liquid crystal display device comprises the liquid crystal composition according to any one of claims 1-8. The liquid crystal display device according to item 9 of the scope of the patent application, wherein the display mode of the liquid crystal display device is a VA type, an IPS type, or a PSA type, and the driving method is an active matrix type.