Negative liquid crystal composition and use thereof

Abstract

The present invention relates to the technical field of liquid crystal materials, and specifically relates to a negative liquid crystal composition and the use thereof. The negative liquid crystal composition of the present invention comprises one or more compounds represented by general formula I, one or more compounds represented by general formula II, one or more compounds represented by general formula III, one or more compounds represented by general formula IV, and one or more compounds represented by general formula V. The compound represented by general formula I is a bicyclohexane neutral compound; the compound represented by general formula II is a bicyclic negative compound; the compound represented by general formula III is a tricyclic negative compound free of biphenyl; the compound represented by general formula IV is a tricyclic negative compound containing biphenyl; and the compound represented by general formula V is a tricyclic neutral compound containing biphenyl. The negative liquid crystal composition of the present invention exhibits good Flicker performance and can alleviate the problem of severe flicker of negative LCDs at low frequencies.

Description

A negative liquid crystal composition and its application Cross-referencing

[0001] This application claims priority to Chinese Patent Application No. 202411808267.3, filed on December 10, 2024, entitled “A Negative Liquid Crystal Composition and Its Application Thereof,” the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This invention relates to the field of liquid crystal materials technology, and more specifically to a negative liquid crystal composition and its application. Background Technology

[0003] Currently, LCD technology is mature, successfully solving technical challenges such as viewing angle, resolution, color saturation, and brightness. Its display performance is approaching or surpassing that of CRT monitors. Large-size and small-to-medium-size LCDs have gradually become the mainstream flat panel display in their respective fields.

[0004] Negative liquid crystal displays were proposed in the late 1980s, primarily used in VA mode. Their main advantage is high contrast, while their main disadvantages are narrow viewing angles and slow response times. With the development of display technology, technologies such as MVA, PVA, and PSVA emerged, solving the problems of response time and viewing angles. In recent years, with touchscreens becoming mainstream in the mobile device market, IPS and FFS hard-screen displays have an inherent advantage. IPS and FFS displays can use either positive or negative liquid crystals. Due to the bending electric field present in these displays, positive liquid crystals align along the electric field lines, causing molecular bending and a decrease in transmittance; negative liquid crystals align perpendicular to the electric field lines, thus significantly increasing transmittance, making it the best method currently available for improving transmittance and reducing backlight power consumption. However, negative liquid crystals also suffer from significant flickering at low frequencies, greatly affecting the viewing experience.

[0005] Specifically, the flicker problem of LCD monitors can be quantified using a flicker value:

[0006]

[0007] In the formula, Tmax is the maximum transmittance and Tmin is the minimum transmittance. Technical issues

[0008] This invention provides a negative liquid crystal composition and its application to solve the problem of severe flickering in existing negative liquid crystals under low-frequency driving. The negative liquid crystal composition of this invention has a good flicker value at low frequencies, which can effectively improve the problem of severe flickering in negative LCDs at low frequencies. Technical solutions

[0009] According to a first aspect of the present invention, the present invention provides a negative liquid crystal composition comprising one or more compounds represented by general formula I, one or more compounds represented by general formula II, one or more compounds represented by general formula III, one or more compounds represented by general formula IV, and one or more compounds represented by general formula V.

[0010] Wherein, the compound represented by general formula I is a neutral bicyclohexane compound; the compound represented by general formula II is a bicyclic negative compound; the compound represented by general formula III is a tricyclic negative compound that does not contain biphenyl; the compound represented by general formula IV is a tricyclic negative compound that contains biphenyl; and the compound represented by general formula V is a tricyclic neutral compound that contains biphenyl.

[0011] In this invention, the compound of general formula I is a neutral bicyclohexane compound with good low-temperature solubility. The compound of general formula II is a bicyclic negative compound with a fast response speed. The compound of general formula III is a tricyclic negative compound with a high clearing point. The compound of general formula IV is a tricyclic negative compound containing biphenyl with a high refractive index. The compound of general formula V is a tricyclic neutral compound containing biphenyl with a high refractive index. This invention provides a negative liquid crystal composition that, through the synergistic effect of compounds represented by general formulas II, III, IV, and V, exhibits excellent flicker performance, effectively improving the flicker problem of negative LCDs, especially at low frequencies.

[0012] Furthermore, the compound represented by general formula I is selected from one or both of the following formulas I1 or I2:

[0013]

[0014] Furthermore, the compound represented by general formula II is selected from one or both of formula II1 or II2:

[0015] .

[0016] Furthermore, the compound represented by general formula III is selected from one or more of formulas III1 to III3:

[0017] .

[0018] Furthermore, the compound represented by general formula IV is selected from one or more of formulas IV1 to IV3:

[0019] .

[0020] Furthermore, the compound represented by general formula IV is selected from one or both of formula V1 or formula V2:

[0021] .

[0022] Furthermore, the negative liquid crystal composition also includes compounds represented by the following general formula VI:

[0023] .

[0024] Furthermore, the negative liquid crystal composition comprises the following components:

[0025] (1) Compounds represented by general formula I with a weight percentage of 20-32%;

[0026] (2) Compounds represented by general formula II in weight percentages of 15-35%;

[0027] (3) Compounds represented by general formula III in weight percentages of 1 to 30%;

[0028] (4) Compounds represented by general formula IV with a weight percentage of 15-30%;

[0029] (5) Compounds represented by general formula V with a weight percentage of 1 to 10%;

[0030] (6) Compounds represented by general formula VI with a weight percentage of 0 to 10%.

[0031] Preferably, the negative liquid crystal composition comprises the following components:

[0032] (1) Compounds represented by general formula I with a weight percentage of 25-32%;

[0033] (2) Compounds represented by general formula II in a weight percentage of 20-32%;

[0034] (3) Compounds represented by general formula III with a weight percentage of 2-10%;

[0035] (4) Compounds represented by general formula IV with a weight percentage of 20-30%;

[0036] (5) Compounds represented by general formula V with a weight percentage of 5 to 10%.

[0037] More preferably, the negative liquid crystal composition comprises the following components:

[0038] (1) Compounds represented by general formula I with a weight percentage of 30-32%;

[0039] (2) Compounds represented by general formula II in a weight percentage of 25-30%;

[0040] (3) Compounds represented by general formula III in a weight percentage of 4-6%;

[0041] (4) Compounds represented by general formula IV with a weight percentage of 25-28%;

[0042] (5) Compounds represented by general formula V with a weight percentage of 9-10%.

[0043] In some specific embodiments, the provided negative liquid crystal composition comprises the components listed in Table 1 below:

[0044] Table 1

[0045]

[0046] Preferably, the negative liquid crystal composition comprises the following components:

[0047] (1) Compounds represented by general formula I with a weight percentage of 22-30%;

[0048] (2) Compounds represented by general formula II in weight percentages of 18-30%;

[0049] (3) Compounds represented by general formula III in weight percentages of 10-30%;

[0050] (4) Compounds represented by general formula IV with a weight percentage of 15-20%;

[0051] (5) Compounds represented by general formula V with a weight percentage of 2-8%;

[0052] (6) Compounds represented by general formula VI with a weight percentage of 2 to 8%.

[0053] More preferably, the negative liquid crystal composition comprises the following components:

[0054] (1) Compounds represented by general formula I with a weight percentage of 25-28%;

[0055] (2) Compounds represented by general formula II in a weight percentage of 20-25%;

[0056] (3) Compounds represented by general formula III in a weight percentage of 22-28%;

[0057] (4) Compounds represented by general formula IV with a weight percentage of 16-19%;

[0058] (5) Compounds represented by general formula V with a weight percentage of 3-5%;

[0059] (6) Compounds represented by general formula VI with a weight percentage of 4 to 6%.

[0060] In some specific embodiments, the provided negative liquid crystal composition includes the components listed in Table 2 below:

[0061] Table 2

[0062]

[0063] There are no particular limitations on the preparation method of the negative liquid crystal composition of the present invention. It can be produced by mixing two or more compounds using conventional methods, such as by mixing different components and dissolving them together at high temperature. In this case, the liquid crystal composition is dissolved in a solvent used for the compound and mixed, and then the solvent is distilled off under reduced pressure. Alternatively, the liquid crystal composition of the present invention can be prepared by conventional methods, such as dissolving a component with a smaller content in a major component with a larger content at a higher temperature, or dissolving each component in an organic solvent, such as acetone, chloroform, or methanol, and then mixing the solutions to remove the solvent.

[0064] According to a second aspect of the present invention, the present invention also provides the use of the above-described negative liquid crystal composition in a liquid crystal display element or liquid crystal display device. Beneficial effects

[0065] The negative liquid crystal composition provided by this invention has low rotational viscosity, large elastic constant, good low-temperature miscibility and flicker performance, and can be used in fast-response liquid crystal displays in various display modes. Its use in VA, IPS or FFS mode displays can significantly improve the display effect of liquid crystal displays, and it is especially suitable for IPS and FFS mode liquid crystal displays. Embodiments of the present invention

[0066] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0067] Unless otherwise stated, percentages in this invention are weight percentages; temperature is in degrees Celsius; Δn represents optical anisotropy (25°C); Δε represents dielectric anisotropy (25°C, 1000Hz); Cp represents the rotational viscosity (mPa·s, 25°C); Cp represents the clearing point of the liquid crystal composition (°C); K 11 K 22 K 33These represent the elastic constants for warp, torsion, and bending, respectively (pN, 25℃).

[0068] In the following embodiments, the group structures in the negative liquid crystal compounds are represented by the codes shown in Table 3.

[0069] Table 3: Group structure codes of liquid crystal compounds

[0070]

[0071] Take the following compound structure as an example:

[0072] It is represented as: 3CWO2.

[0073] It is represented as: 2CPWO2.

[0074] In the following embodiments, the negative liquid crystal composition is prepared by a thermal dissolution method, including the following steps: weighing the liquid crystal compound by weight percentage using a balance, wherein there is no specific requirement for the order of weighing and adding, usually weighing and mixing in order of the melting point of the liquid crystal compound from high to low, heating and stirring at 60~100℃ to make the components melt evenly, then filtering, rotary evaporating, and finally encapsulating to obtain the target sample.

[0075] In the following embodiments, the weight percentage of each component in the negative liquid crystal composition and the performance parameters of the liquid crystal composition are shown in the following table.

[0076] Example 1

[0077] This embodiment provides a negative liquid crystal composition, the weight percentage of each component and its performance parameters are shown in Table 4 below.

[0078] Table 4: Weight percentage and performance parameters of each component in the liquid crystal composition

[0079]

[0080] Example 2

[0081] This embodiment provides a negative liquid crystal composition, the weight percentage of each component and its performance parameters are shown in Table 5 below.

[0082] Table 5: Weight percentage and performance parameters of each component in the liquid crystal composition

[0083]

[0084] Comparative Example

[0085] This comparative example provides a negative liquid crystal composition, the weight percentage of each component and its performance parameters are shown in Table 6 below.

[0086] Table 6: Weight percentage and performance parameters of each component in the liquid crystal composition

[0087]

[0088] The flicker values ​​of the examples and comparative examples were tested at 120Hz, 60Hz, 30Hz, 20Hz and 1Hz. The test results are shown in Table 7 below.

[0089] Table 7

[0090]

[0091] Note: The smaller the Flicker value, the less flickering and the less noticeable the flickering.

[0092] The experimental data in Table 5 show that at high frequencies (120Hz and 60Hz), there is no significant difference in the flicker values ​​between the negative liquid crystal compositions of the present invention and the comparative examples; however, at low frequencies (20Hz and 1Hz), the flicker values ​​of the negative liquid crystal compositions of the present invention are significantly better than those of the comparative examples.

[0093] As can be seen from the above embodiments, the negative liquid crystal composition provided by the present invention has low rotational viscosity, high resistivity, good low-temperature miscibility, large elastic constant, and excellent light and thermal stability, which can effectively reduce the flicker value of liquid crystal materials, thereby solving the flicker problem of liquid crystal displays under low-frequency driving conditions. Therefore, the negative liquid crystal composition provided by the present invention is suitable for IPS and FFS type TFT liquid crystal display devices.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Industrial applicability

[0095] The negative liquid crystal composition provided by this invention possesses low rotational viscosity, high resistivity, good low-temperature miscibility, a large elastic constant, and excellent photostability and thermal stability. It can effectively reduce the flicker value of liquid crystal materials, thereby solving the flicker problem of liquid crystal displays under low-frequency driving conditions. Therefore, the negative liquid crystal composition provided by this invention is suitable for IPS and FFS type TFT liquid crystal display devices.

Claims

1. A negative liquid crystal composition, characterized in that, It includes one or more compounds represented by general formula I, one or more compounds represented by general formula II, one or more compounds represented by general formula III, one or more compounds represented by general formula IV, and one or more compounds represented by general formula V. Wherein, the compound represented by general formula I is a neutral bicyclohexane compound; the compound represented by general formula II is a bicyclic negative compound; the compound represented by general formula III is a tricyclic negative compound that does not contain biphenyl; the compound represented by general formula IV is a tricyclic negative compound that contains biphenyl; and the compound represented by general formula V is a tricyclic neutral compound that contains biphenyl.

2. The negative liquid crystal composition according to claim 1, characterized in that, The compound represented by general formula I is selected from one or both of the following formulas I1 or I2: ； And / or, the compound represented by general formula II is selected from one or both of formula II1 or II2: 。 3. The negative liquid crystal composition according to claim 1, characterized in that, The compound represented by general formula III is selected from one or more of formulas III1 to III3: 。 4. The negative liquid crystal composition according to claim 1, characterized in that, The compound represented by general formula IV is selected from one or more of formulas IV1 to IV3: 。 5. The negative liquid crystal composition according to claim 1, characterized in that, The compound represented by general formula IV is selected from one or both of formula V1 or V2: 。 6. The negative liquid crystal composition according to any one of claims 1-5, characterized in that, It also includes compounds represented by the following general formula VI: 。 7. The negative liquid crystal composition according to any one of claims 1-6, characterized in that, Includes the following components: (1) Compounds represented by general formula I with a weight percentage of 20-32%; (2) Compounds represented by general formula II in weight percentages of 15-35%; (3) Compounds represented by general formula III in weight percentages of 1 to 30%; (4) Compounds represented by general formula IV with a weight percentage of 15-30%; (5) Compounds represented by general formula V with a weight percentage of 1 to 10%; (6) Compounds represented by general formula VI with a weight percentage of 0 to 10%.

8. The negative liquid crystal composition according to claim 7, characterized in that, Includes the following components: (1) Compounds represented by general formula I with a weight percentage of 25-32%; (2) Compounds represented by general formula II in a weight percentage of 20-32%; (3) Compounds represented by general formula III with a weight percentage of 2-10%; (4) Compounds represented by general formula IV with a weight percentage of 20-30%; (5) Compounds represented by general formula V with a weight percentage of 5-10%; Preferably, it comprises the following components: (1) Compounds represented by general formula I with a weight percentage of 30-32%; (2) Compounds represented by general formula II in a weight percentage of 25-30%; (3) Compounds represented by general formula III in a weight percentage of 4-6%; (4) Compounds represented by general formula IV with a weight percentage of 25-28%; (5) Compounds represented by general formula V with a weight percentage of 9-10%.

9. The negative liquid crystal composition according to claim 7, characterized in that, Includes the following components: (1) Compounds represented by general formula I with a weight percentage of 22-30%; (2) Compounds represented by general formula II in weight percentages of 18-30%; (3) Compounds represented by general formula III in weight percentages of 10-30%; (4) Compounds represented by general formula IV with a weight percentage of 15-20%; (5) Compounds represented by general formula V with a weight percentage of 2-8%; (6) Compounds represented by general formula VI with a weight percentage of 2-8%; Preferably, it comprises the following components: (1) Compounds represented by general formula I with a weight percentage of 25-28%; (2) Compounds represented by general formula II in a weight percentage of 20-25%; (3) Compounds represented by general formula III in a weight percentage of 22-28%; (4) Compounds represented by general formula IV with a weight percentage of 16-19%; (5) Compounds represented by general formula V with a weight percentage of 3-5%; (6) Compounds represented by general formula VI with a weight percentage of 4 to 6%.

10. The use of the negative liquid crystal composition according to any one of claims 1-9 in a liquid crystal display element or liquid crystal display device.

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