Dielectric positive liquid crystal composition and application thereof

Abstract

The invention relates to a dielectric positive liquid crystal composition and application thereof, and belongs to the field of liquid crystal materials. The dielectric positive liquid crystal composition comprises at least one compound with a structure as shown in a general formula I: # imgabs0 #, at least one compound as shown in a general formula F: # imgabs1 #, at least one compound as shown in a general formula N: # imgabs2 # and at least one compound as shown in a general formula D: # imgabs3 #. The liquid crystal composition provided by the invention has the advantages of larger Kave, large refractive index, quick response, high penetration rate and the like; the liquid crystal display device containing the liquid crystal composition has the advantages of high response speed, high contrast ratio and high transmittance. According to the liquid crystal composition, the compound shown in the general formula I is added, so that the liquid crystal composition has higher optical anisotropy and higher average elastic constant, the technical effect of effectively adjusting the transmittance can be realized, and a liquid crystal display device obtains relatively less light scattering; therefore, the liquid crystal display device using the liquid crystal composition can obtain a good display effect.

Description

Technical Field

[0001] The present invention relates to a liquid crystal composition and application thereof, in particular to a dielectric positive liquid crystal composition and application thereof, belonging to the field of liquid crystal materials. Background Art

[0002] In modern technology, liquid crystal displays (LCD) have developed rapidly due to their small size, light weight, low power consumption and excellent display quality, and have been widely used in portable electronic information products. With the increase in the size of LCD screens used in portable computers, office applications, and video applications, there are still some problems to be solved in order to enable LCDs to be used for large-screen displays and eventually replace cathode ray tubes (CRTs), such as improving viewing angle characteristics, increasing response speed, increasing contrast, increasing transmittance, and improving low-temperature stability. The viewing angle of LCD is relatively narrow, which means that when observing away from the direction perpendicular to the normal of the liquid crystal box, the contrast is significantly reduced. When the viewing angle is large, grayscale and color inversion will occur, which seriously affects the display quality of LCD.

[0003] In the early 1970s, experimental research on the basic electro-optical properties of uniformly arranged and twistedly arranged nematic liquid crystal IPS mode has been carried out. Its characteristics are that a pair of electrodes are made on the same substrate, while there is no electrode on the other substrate. The lateral electric field between the pair of electrodes is used to control the arrangement of liquid crystal molecules. Therefore, this mode can also be called the lateral field mode. In the IPS mode, the nematic phase liquid crystal molecules are evenly arranged in parallel between the two substrates, and the two polarizers are placed orthogonally. When the electric field is not applied to the IPS mode, 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 large viewing angles and accurate color reproduction, but the disadvantages are serious light leakage, slow response speed, and high energy consumption.

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

[0005] Based on the traditional IPS-LCD light leakage performance test, technicians in this field have found that the main causes of the light leakage problem of 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.

[0006] According to the following relationship: Wherein, d represents the spacing of the liquid crystal cell, Δn represents the optical anisotropy, ne represents the extraordinary light refractive index, no represents the ordinary light refractive index, and Kave represents the average elastic constant (K11 is the splay elastic constant, K22 is the twist elastic constant, and K33 is the bending elastic constant). If the light scattering of the liquid crystal material is to be improved, Kave needs to be increased. When Kave is increased, the light leakage of the liquid crystal material can be reduced.

[0007] In addition, the delay (Δn.d) of the liquid crystal component should be kept within a certain range when it is designed. The liquid crystal composition with a large absolute value of dielectric anisotropy and a large optical anisotropy has a high rotational viscosity. In order to improve the response speed, it can be achieved by reducing the thickness of the liquid crystal component, that is, reducing the cell gap (d), which requires the liquid crystal composition to have a high optical anisotropy Δn. Paradoxically, liquid crystal compositions with high birefringence generally have a high rotational viscosity, and the low-temperature miscibility of the components is also poor.

[0008] In view of the above situation, the following methods can be considered to improve the transmittance: increasing the average elastic constant Kave of the liquid crystal composition to make the liquid crystal molecules more orderly and less leaking, thereby improving the transmittance. While increasing the optical anisotropy, the rotational viscosity of the liquid crystal composition is increased.

[0009] From the perspective of liquid crystal material preparation, the various properties of liquid crystal materials influence each other, and the improvement of a certain performance index may cause changes in other properties. Therefore, the preparation of liquid crystal materials with suitable properties in all aspects often requires creative labor. Summary of the invention

[0010] In view of the defects of the prior art, the present invention provides a liquid crystal phase with a wide temperature range, low viscosity, large average elastic constant Kave, high optical anisotropy, high birefringence, good solubility at low temperature, high specific resistance and voltage holding rate, high transmittance, and a liquid crystal composition with positive Δε stable to heat and light, and provides an IPS and TN type display element with excellent display quality and not prone to residual by using the liquid crystal composition. The liquid crystal composition of the present invention comprises a terphenyl derivative and a positive component.

[0011] A dielectric positive liquid crystal composition, comprising: at least one compound of the structure shown in general formula I as a first component:

[0012]

[0013] Among them, R 1 represents H, halogen or alkyl of 1-15 carbons;

[0014] X 1 , X 2 There is only one F, and the other one is H;

[0015] m represents an integer from 1 to 8;

[0016] It also contains at least one compound represented by the general formula F as a second component:

[0017]

[0018] Among them, rings B1 and B2 are independent of each other. One or more H on the molecule may be replaced by F;

[0019] R B1 , R B2 each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkenyloxy group having 2 to 12 carbon atoms, wherein one or more H in the alkyl group, the alkoxy group, the alkenyl group or the alkenyloxy group may be substituted by F or Cl;

[0020] L B1 , L B2 Each independently represents F, Cl, CH 3 or CF 3 ;

[0021] b represents 0 or 1;

[0022] It also contains at least one compound represented by the general formula N as a third component:

[0023]

[0024] Among them, R N1 , R N2 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms;

[0025] Rings N1, N2, and N3 are represented independently At least one of and At most one H on can be replaced by F;

[0026] Z N1 , Z N2 Each independently represents a CC single bond, -CH 2 CH 2 -、-CF 2 O-、-OCF 2 -、-CH 2 O-、-OCH 2 -、-CO-O-、-C 2 F 4 -or-CF=CF-;

[0027] c and d each independently represent 0, 1 or 2;

[0028] And at least one compound represented by general formula D as the fourth component:

[0029]

[0030] Among them, R D1 , R D2 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms;

[0031] Rings D1, D2, and D3 each independently represent and One or more H in the above may be replaced by F;

[0032] p and q each independently represent 0, 1 or 2.

[0033] In the liquid crystal composition, calculated by mass percentage, the content of the compound represented by general formula I is 1-40%, the content of the compound represented by general formula F is 1-40%, the content of the compound represented by general formula N is 1-50%, and the content of the compound represented by general formula D is 1-60%.

[0034] Furthermore, the liquid crystal compound represented by the general formula I is preferably a compound of the following structural formula:

[0035] and / or

[0036]

[0037] Among them, R 1 represents H, halogen or alkyl group of 1-15 carbon atoms; and n represents an integer of 1-8.

[0038] Furthermore, the compound represented by general formula I is selected from one or more compounds in the group consisting of the following compounds I-1 to I-21:

[0039]

[0040]

[0041] Further, the compound of general formula I is selected from the combination of any two or more compounds represented by the general formulas of general formulas I-2, I-3, I-5, I-11, I-12, I-14 and I-15. For example, it is selected from the combination of general formulas I-2, I-3 and I-5, I-11, I-12 and I-15, I-11, I-12 and I-14, I-2 and I-3, and I-3 and I-12.

[0042] In the embodiment of the present invention, preferably, the compound of general formula I accounts for 1-40% of the total weight of the liquid crystal composition; more preferably, the compound of general formula I accounts for 5-40wt%, 5-35wt%, 7-40wt% or 10-25% of the total weight of the liquid crystal composition. The compound of general formula I provided by the present invention can help to improve the refractive index of the liquid crystal composition, while too high a content thereof will lead to a decrease in the low-temperature miscibility of the liquid crystal composition.

[0043] Furthermore, the compound represented by the general formula F is selected from one or more compounds in the group consisting of the following compounds F-1 to F-23:

[0044]

[0045]

[0046]

[0047] Among them, R B1 , R B2 Each independently of one another represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms or an alkenyloxy group having 2 to 12 carbon atoms, wherein one or more H in the alkyl group, the alkoxy group, the alkenyl group or the alkenyloxy group may be substituted by F or Cl.

[0048] In an embodiment of the present invention, the content of the compound represented by the general formula F in the liquid crystal composition is 1-40wt%; wherein the mass fraction of the compound represented by the formula F can be 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25% or 28%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. By adding the compound represented by the general formula F to the composition, it can help to achieve a high K ave , fast response and other characteristics.

[0049] In some embodiments of the present invention, the compound of formula N is selected from one or more of the group consisting of the following compounds NA to NE:

[0050]

[0051] In some embodiments of the present invention, the compound represented by the general formula N is particularly preferably selected from one or more of the group consisting of the following compounds NB-1 to NE-2:

[0052]

[0053] In the embodiment of the present invention, the content of the compound of the general formula N in the liquid crystal composition is 1-50%, wherein the mass fraction of the compound represented by formula N can be 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 40% or 45%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. By adding the compound of the general formula N to the composition, the low-temperature miscibility of the liquid crystal composition can be effectively improved.

[0054] Furthermore, the compound represented by the general formula D is one or more compounds selected from the group consisting of the following compounds D-1 to D-20:

[0055]

[0056]

[0057] Among them, R D1 , R D2 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms.

[0058] In the embodiment of the present invention, the content of the compound of the general formula D in the liquid crystal composition is 1-60wt%, wherein the mass fraction of the compound represented by formula N can be 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 40% or 45%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. By adding the compound of the general formula D to the composition, the refractive index can be effectively increased, and the K ave Constant, improving low temperature miscibility.

[0059] Furthermore, the dielectric positive liquid crystal composition further comprises one or more compounds represented by general formula II:

[0060]

[0061] Among them, R C1 represents 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;

[0062] The rings C1, C2, and C3 are independent of each other. One or more H on the benzene ring can be replaced by F;

[0063] L C1 and L C2 Each independently represents H, F, Cl, CH 3 or CF 3 ;

[0064] e represents 0 or 1.

[0065] The compound represented by general formula II is selected from one or more compounds represented by general formula II-a to II-h:

[0066]

[0067] Among them, R C1 represents 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; L C1 and L C2 Each independently represents H, F, Cl, CH 3 or CF 3 .

[0068] Furthermore, the compound represented by the general formula II includes the following compounds II-1-1 to II-1-6:

[0069]

[0070] Furthermore, the compound represented by the general formula II is selected from one or more of the group consisting of the following compounds II-1 to II-31:

[0071]

[0072]

[0073] Among them, R C1 It represents 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.

[0074] In the embodiment of the present invention, the content of the compound represented by the general formula II in the liquid crystal composition is 1-40wt%, wherein the mass fraction of the compound represented by the formula N can be 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 33%, 36% or 39%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. By adding the compound represented by the general formula II to the composition, the refractive index can be effectively increased, and the K ave constant.

[0075] Furthermore, the liquid crystal composition may further comprise one or more additives known to those skilled in the art and described in the literature. For example, 0-15% of a dopant may be added.

[0076] The following are possible dopants which are preferably added to the liquid crystal composition of the present invention:

[0077]

[0078]

[0079] In some embodiments of the present invention, preferably, the weight percentage of the dopant in the liquid crystal composition is 0-5%; more preferably, the weight percentage of the dopant in the liquid crystal composition is 0-1%.

[0080] In addition to the above compounds, the liquid crystal composition of the present invention may also contain conventional nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, antioxidant, ultraviolet absorber, infrared absorber, polymerizable monomer or light stabilizer.

[0081] The antioxidant, light stabilizer and other additives used in the liquid crystal composition of the present invention are preferably one or more of the following compounds:

[0082]

[0083]

[0084]

[0085] Here, n represents a positive integer from 1 to 20.

[0086] Preferably, the light stabilizer is selected from the light stabilizers shown below:

[0087]

[0088] In an embodiment of the present invention, the stabilizer preferably accounts for 0-5% of the total weight of the liquid crystal composition; more preferably, the stabilizer accounts for 0-1% of the total weight of the liquid crystal composition; as a particularly preferred solution, the stabilizer accounts for 0.01-0.1% of the total weight of the liquid crystal composition.

[0089] Another aspect of the present invention provides an application of a dielectric positive liquid crystal composition in preparing a liquid crystal display device. A liquid crystal display device comprising the liquid crystal composition provided by the present invention includes a TN, IPS and FFS mode liquid crystal display device.

[0090] Beneficial effects:

[0091] The liquid crystal composition provided by the present invention has a large K ave , large refractive index, fast response, high transmittance and other advantages, so that the liquid crystal display device containing the liquid crystal composition of the present invention has a faster response speed, high contrast, and high transmittance. In particular, in the liquid crystal composition of the present invention, when the compound of general formula I is added, the liquid crystal composition has a higher optical anisotropy and a higher average elastic constant, so the compound of general formula I can achieve the technical effect of effectively adjusting the transmittance, and then the liquid crystal display device of the present invention can obtain relatively less light scattering, so the liquid crystal display device using the liquid crystal composition of the present invention can obtain a good display effect.

[0092] The liquid crystal composition of the present invention has positive dielectric properties, low rotational viscosity, high birefringence, good low-temperature miscibility, good light and heat stability, and has fast response speed, low image viscosity and poor display when used in liquid crystal display elements.

[0093] The liquid crystal composition provided by the present invention has appropriately high optical anisotropy, low viscosity, high low-temperature miscibility, and a large average elastic constant Kave, so that a liquid crystal display device containing the liquid crystal composition of the present invention has a faster response speed, a high contrast, a higher transmittance, and relatively less light scattering. Therefore, the liquid crystal composition of the present invention can enable the liquid crystal display device containing the liquid crystal composition to obtain a good display effect. DETAILED DESCRIPTION

[0094] For ease of expression, in the following embodiments, the group structures of the liquid crystal compositions are represented by the codes listed in Table 1.

[0095] Table 1 Group structure codes of liquid crystal compounds

[0096]

[0097]

[0098] Take the following compound as an example:

[0099]

[0100] The structural formula can be expressed as follows: nCPGF, where n represents the number of atoms of the left-end alkyl group. For example, if n is "3", it means that the alkyl group is -C 3 H 7 ; In the code, C represents cyclohexyl, P represents 1,4-phenylene, G represents 2-fluoro-1,4-phenylene, and F represents fluorine.

[0101] The abbreviated codes for the test items in the following embodiments are as follows:

[0102] Cp: ​​clearing point (nematic-isotropic phase transition temperature, °C);

[0103] T S→N : Low temperature phase transition point (smectic phase-nematic phase transition temperature, °C);

[0104] Δn: optical anisotropy (589 nm, 25 °C);

[0105] Δε: dielectric anisotropy (1KHz, 25℃);

[0106] K 11 : elastic constant (“slope spread”, pN at 20°C);

[0107] K 22 : elastic constant (“distortion”, pN at 20°C);

[0108] K 33 : elastic constant (“bending”, pN at 20°C);

[0109] K ave : Average elastic constant (K 11 +K 22 +K 33 the average value of );

[0110] t -30℃ : The liquid crystal medium is placed in a glass bottle and stored at -30°C, and the time recorded when crystal precipitation is observed;

[0111] γ 1 : rotational viscosity;

[0112] τ: response time (ms);

[0113] The optical anisotropy was measured using an Abbe refractometer under a sodium lamp (589 nm) at 25°C. Δε=ε‖-ε⊥, where ε‖ is the dielectric constant parallel to the molecular axis, and ε⊥ is the dielectric constant perpendicular to the molecular axis. The test conditions are: LCR instrument, 25°C, 1KHz, TN type test box, and 4μm thickness.

[0114] K 11 , K 22 , K 33 It was measured using INSTEC ALCT-PP1 at 25°C, with a test cell of type 5 and a cell thickness of 18μm.

[0115] τ response time is measured using LCT-5016 at 25°C, 1KHz, TN type test box, and 4μm thickness.

[0116] Each component 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 compounds meet the standards of electronic compounds after testing. The composition of each liquid crystal composition and the test results of its performance parameters are shown below.

[0117] Comparative Example 1

[0118] A liquid crystal composition of Comparative Example 1 was prepared according to the compounds and weight percentages listed in Table 2, and filled between two substrates of a liquid crystal display for performance testing.

[0119] Table 2 Liquid crystal composition formula and performance parameter test

[0120]

[0121] Example 1

[0122] The liquid crystal composition of Example 1 was prepared according to the compounds and weight percentages listed in Table 3, and filled between two substrates of a liquid crystal display for performance testing.

[0123] Table 3 Liquid crystal composition formula and performance parameter test

[0124]

[0125]

[0126] Example 2

[0127] The liquid crystal composition of Example 2 was prepared according to the compounds and weight percentages listed in Table 4, and filled between two substrates of a liquid crystal display for performance testing.

[0128] Table 4 Liquid crystal composition formula and performance parameter test

[0129]

[0130] Example 3

[0131] The liquid crystal composition of Example 3 was prepared according to the compounds and weight percentages listed in Table 5, and filled between two substrates of a liquid crystal display for performance testing.

[0132] Table 5 Liquid crystal composition formula and performance parameter test

[0133]

[0134]

[0135] Example 4

[0136] The liquid crystal composition of Example 4 was prepared according to the compounds and weight percentages listed in Table 6, and filled between two substrates of a liquid crystal display for performance testing.

[0137] Table 6 Liquid crystal composition formula and performance parameter test

[0138]

[0139] Example 5

[0140] The liquid crystal composition of Example 5 was prepared according to the compounds and weight percentages listed in Table 7, and filled between two substrates of a liquid crystal display for performance testing.

[0141] Table 7 Liquid crystal composition formula and performance parameter test

[0142]

[0143] In the above Example 5, 300 ppm of additives were additionally added:

[0144]

[0145] Example 6

[0146] The liquid crystal composition of Example 6 was prepared according to the compounds and weight percentages listed in Table 8, and filled between two substrates of a liquid crystal display for performance testing.

[0147] Table 8 Liquid crystal composition formula and performance parameter test

[0148]

[0149]

[0150] Example 7

[0151] The liquid crystal composition of Example 7 was prepared according to the compounds and weight percentages listed in Table 9, and filled between two substrates of a liquid crystal display for performance testing.

[0152] Table 9 Liquid crystal composition formula and performance parameter test

[0153]

[0154] Example 8

[0155] The liquid crystal composition of Example 8 was prepared according to the compounds and weight percentages listed in Table 10, and filled between two substrates of a liquid crystal display for performance testing.

[0156] Table 10 Liquid crystal composition formula and performance parameter test

[0157]

[0158] In the above Example 8, 300 ppm of additives were additionally added:

[0159]

[0160] It can be seen from the above comparative example 1 and embodiments 1-8 that the liquid crystal composition provided by the present invention has appropriately high optical anisotropy, low viscosity, high low-temperature miscibility, and a large average elastic constant Kave, so that the liquid crystal display device containing the liquid crystal composition of the present invention has a faster response speed, high contrast, higher transmittance, and relatively less light scattering. Therefore, the liquid crystal composition of the present invention can enable the liquid crystal display device containing the liquid crystal composition to obtain a good display effect.

[0161] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A dielectric positive liquid crystal composition comprising at least one compound having a structure shown in general formula I: in, R 1 represents H, halogen or alkyl of 1-15 carbons; X 1 and X 2 One of them represents F and the other represents H; m represents an integer from 1 to 8; At least one compound represented by the general formula F: Among them, rings B1 and B2 are independently represented One or more H on the molecule may be replaced by F; R B1 , R B2 Each independently represents an alkyl group of 1 to 12 carbon atoms, an alkoxy group of 1 to 12 carbon atoms, an alkenyl group of 2 to 12 carbon atoms, or an alkenyloxy group of 2 to 12 carbon atoms, wherein one or more H in the alkyl group, alkoxy group, alkenyl group or alkenyloxy group may be substituted with F or Cl; L B1 , L B2 Each independently represents F, Cl, CH 3 or CF 3 ; b represents 0 or 1; At least one compound represented by the general formula N: Among them, R N1 , R N2 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Rings N1, N2, and N3 are represented independently At least one of and At most one H on can be replaced by F; Z N1 , Z N2 Each independently represents a CC single bond, -CH 2 CH 2 -、-CF 2 O-、-OCF 2 -、-CH 2 O-、-OCH 2 -、-CO-O-、-C 2 F 4 -or-CF=CF-; c and d each independently represent 0, 1 or 2; And at least one compound represented by general formula D: Among them, R D1 , R D2 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms; Rings D1, D2, and D3 each independently represent and One or more H in the above may be replaced by F; p and q each independently represent 0, 1 or 2.

2. The dielectric positive liquid crystal composition according to claim 1, Features: Calculated by mass percentage, the content of the compound represented by general formula I is 1-40%, the content of the compound represented by general formula F is 1-40%, the content of the compound represented by general formula N is 1-50%, and the content of the compound represented by general formula D is 1-60%.

3. The dielectric positive liquid crystal composition according to claim 1, Features: The liquid crystal compound represented by the general formula I is a compound of the following structural formula: and / or Here, n represents an integer from 1 to 8.

4. The dielectric positive liquid crystal composition according to claim 3, Features: The compound represented by general formula I is one or more selected from the group consisting of compounds I-1 to I-21:

5. The dielectric positive liquid crystal composition according to claim 1, Features: The compound represented by general formula F is one or more selected from the group consisting of compounds F-1 to F-23:

6. The dielectric positive liquid crystal composition according to claim 1, Features: The compound represented by the general formula N is selected from one or more of the group consisting of compounds NA to NE:

7. The dielectric positive liquid crystal composition according to claim 1, Features: The dielectric positive liquid crystal composition further comprises one or more compounds represented by general formula II: Among them, R C1 represents 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; Rings C1, C2, and C3 are represented independently One or more H on the benzene ring can be replaced by F; L C1 and L C2 Each independently represents H, F, Cl, CH 3 or CF 3 ; e represents 0 or 1; Calculated by mass percentage, the content of the compound represented by general formula II is 1-40%.

8. The dielectric positive liquid crystal composition according to claim 7, Features: The compound represented by general formula II is selected from one or more compounds represented by general formula II-a to II-h:

9. The dielectric positive liquid crystal composition according to any one of claims 1 to 8, Features: The liquid crystal mixture further comprises one or more dopants and / or one or more stabilizers. The content of the dopants is 0-15% by mass of the entire liquid crystal composition, and the content of the stabilizers is 0-5% by mass.

10. Use of the dielectric positive liquid crystal composition according to any one of claims 1 to 9 in preparing a liquid crystal display device, wherein the liquid crystal display device includes a TN, IPS and FFS mode liquid crystal display device.

Images