Liquid crystal composition, liquid crystal display element, or liquid crystal display

Abstract

The present application discloses a kind of cholesteric liquid crystal compositions, the liquid crystal composition contains one or more compounds shown in formula I, one or more compounds shown in formula II, one or more compounds shown in formula III, one or more compounds shown in formula IV and one or more chiral active substances.The liquid crystal composition of the present application has large optical anisotropy (Δn≥0.22), large dielectric anisotropy, super wide operating temperature range (-30~95℃), good reliability, especially high contrast (contrast >25), small wavelength change at different temperatures (△λ≤20nm), and the liquid crystal composition can improve the jitter of liquid crystal display, and can have excellent anti-shock performance in vehicle environment, especially good anti-vibration performance at -30℃ and 90℃.It can be widely used in liquid crystal electronic book, outdoor and vehicle display and other optical devices.

Description

Technical Field

[0001] This invention relates to a cholesteric liquid crystal composition and a liquid crystal display element or liquid crystal display using the same, and is mainly applicable to the technical fields of liquid crystal e-books, electronic signage, bistable liquid crystal displays, etc. Background Technology

[0002] Cholesteric liquid crystal e-books offer advantages such as high contrast and zero power consumption while displaying content, making them a viable alternative to paper in daily life. They are primarily used in e-books, electronic tags, and display panels. Cholesteric liquid crystal compositions are obtained by adding optically active chiral agents to a stochastic liquid crystal. The planar and focal conic states of cholesteric liquid crystals are stable and can maintain stability over long periods, thus exhibiting bistable properties.

[0003] Cholesteric liquid crystals exhibit Bragg reflection in their planar state. The reflection wavelength (λ) is determined by the average refractive index (n) of the liquid crystal composition and the chiral pitch (P), where λ = n 平均 ×P. When the refractive index of the liquid crystal composition is fixed, the chiral pitch P can be adjusted by increasing or decreasing the amount of chiral compound, thereby obtaining different reflected wavelengths of colors. The reflected wavelength range is generally 400-760nm. At the same pitch, the wavelength of reflected light is proportional to the anisotropy of the refractive index of the liquid crystal (Δn = ne - no). To achieve high brightness of reflection, a liquid crystal composition with a large Δn is required. However, to increase the refractive index of the liquid crystal composition, a polycyclic liquid crystal compound with a large refractive index is required. Increasing the content of such compounds will lead to a deterioration in low-temperature performance. Moreover, a higher refractive index of the liquid crystal composition does not necessarily result in high contrast. For example, the highest contrast ratio in patent CN104745202A is 5.1. Therefore, only a reasonable combination of liquid crystal types can achieve high contrast while maintaining good low-temperature performance.

[0004] Currently, the operating temperature range of cholesteric liquid crystals (CLCs) on the market is generally -20 to 70°C, while that of e-ink displays is generally -20 to 60°C. The operating temperature range of mainstream CLC display technologies is not significantly different from that of e-ink displays. In a market dominated by e-ink e-books, CLCs cannot surpass the operating temperature range of e-ink to compete for market share. Furthermore, significant changes in the reflection wavelength of CLC compositions at different temperatures can cause RGB color drift, leading to color display distortion. Moreover, the driving voltage varies at different temperatures—higher at low temperatures and lower at high temperatures—with a voltage difference ΔV > 15V, resulting in complex driving circuit design and high circuit costs. Therefore, a well-designed liquid crystal formulation can reduce the magnitude of this voltage difference.

[0005] Electronic ink e-paper uses black and white charged particles as the display medium. These particles move under the influence of an electric field within the e-ink screen capsule; when the power is removed, the particles retain their state, thus forming a display. In a vehicle environment, due to accumulated road and engine vibrations, continuous vibration can cause a small amount of black and white particles to settle, causing the text on the e-ink screen to fade or even disappear. Liquid crystals, relying on interface and polymer stabilization, have a greater advantage in shock resistance. A well-designed cholesteric liquid crystal can further enhance the shock resistance of cholesteric liquid crystal e-paper in high and low temperature environments.

[0006] Cholesteric liquid crystals used in electronic paper generally have a high dielectric constant. After aging, prolonged operation, or high-temperature operation, ions are easily released from the liquid crystal composition or glass. Polar liquid crystal molecules readily adsorb these ions. Moreover, cholesteric liquid crystals typically use low-frequency driving. Under low-frequency driving, the continuous disturbance of ions released from the liquid crystal composition or glass causes instability of the liquid crystal molecules, resulting in continuous pixel flickering in the device, which is unacceptable to consumers.

[0007] Therefore, it is urgent to develop liquid crystal compositions with high dielectric constant, ultra-wide operating temperature range, high contrast, small wavelength variation and VOP variation at different temperatures, high charge retention rate, and especially good anti-shake and anti-vibration performance. Summary of the Invention

[0008] This invention provides a new technical solution that can solve the above-mentioned technical problems.

[0009] The liquid crystal composition of this invention exhibits high optical anisotropy (Δn≥0.22), high dielectric anisotropy, an ultra-wide operating temperature range (-30~95℃), good reliability, especially high contrast ratio (contrast ratio>25), and small wavelength variation at different temperatures (Δλ≤20nm). Furthermore, this liquid crystal composition can improve the flickering performance of liquid crystal displays and provides excellent shock resistance in automotive environments, particularly at -30℃ and 90℃. It can be widely used in optical devices such as wide-temperature liquid crystal e-books and outdoor and automotive liquid crystal displays with stringent temperature requirements.

[0010] Specifically, the present invention provides a cholesteric liquid crystal composition comprising one or more compounds of formula I, one or more compounds of formula II, one or more compounds of formula III, one or more compounds of formula IV, and one or more chiral active substances.

[0011]

[0012] in,

[0013] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, a fluorinated alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, a fluorinated alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, a fluorinated alkenyl group having 2-6 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms, and any one or more of the -CH2- groups shown in R1, R3, R4, and R6 may optionally be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0014] X1, X2, X3, X4, X5, and X6 each independently represent H or F;

[0015] m represents 0 or 1;

[0016] Z1, Z2, and Z3 each independently represent a single bond or -COO-;

[0017] Each represents independently

[0018] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula V:

[0019]

[0020] in,

[0021] R7 represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms, wherein any one or more of the -CH2- groups represented by R7 may be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0022] n represents 0 or 1.

[0023] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VI.

[0024]

[0025] in,

[0026] R8 and R9 each independently represent an alkyl group with 1-6 carbon atoms, an alkoxy group with 1-6 carbon atoms, or an alkenyl group with 2-6 carbon atoms;

[0027] r represents 0 or 1.

[0028] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VII.

[0029]

[0030] in,

[0031] R 10 R 11 Each can independently represent F, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms;

[0032] Each represents independently

[0033] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VIII.

[0034]

[0035] in,

[0036] R 12 R represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms. 12 Any one or more of the -CH2- groups shown may be optionally replaced by cyclopentylene, cyclobutylene, or cyclopropylene;

[0037] express

[0038] express

[0039] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula IX.

[0040]

[0041] in,

[0042] R 13 R 14 Each can independently represent an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms;

[0043] express

[0044] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula XII.

[0045]

[0046] in,

[0047] R 15 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

[0048] The cholesteric liquid crystal composition of the present invention preferably has an ultrawide operating temperature range of -30 to 95°C, and the wavelength change at different temperatures is less than or equal to 20 nm, i.e., Δλ≤20 nm.

[0049] The cholesteric liquid crystal composition of the present invention preferably has a large optical anisotropy Δn≥0.22, a contrast ratio greater than 25, and a high charge retention rate (VHR), and can be widely used in optical devices such as liquid crystal e-books, outdoor and automotive displays.

[0050] The present invention provides a cholesteric liquid crystal display element comprising the cholesteric liquid crystal composition of the present invention, wherein the cholesteric liquid crystal display element is an active matrix addressing display element or a passive matrix addressing display element.

[0051] The present invention provides a cholesteric liquid crystal display comprising the cholesteric liquid crystal composition of the present invention, wherein the cholesteric liquid crystal display is an active matrix addressing display or a passive matrix addressing display.

[0052] Invention Effects

[0053] The liquid crystal composition of this invention exhibits high optical anisotropy (Δn≥0.22), high dielectric anisotropy, an ultra-wide operating temperature range (-30~95℃), good reliability, especially high contrast ratio (contrast ratio>25), and small wavelength variation at different temperatures (Δλ≤20nm). Furthermore, this liquid crystal composition can improve pixel jitter issues in liquid crystal displays. Simultaneously, the liquid crystal composition of this invention has good alignment with the PI film, thus providing excellent shock resistance in automotive environments, particularly at -30℃ and 90℃. It can be widely used in optical devices such as liquid crystal e-books, outdoor and automotive displays. Detailed Implementation

[0054] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0055] Liquid crystal composition

[0056] This invention provides a cholesteric liquid crystal composition comprising one or more compounds of formula I, one or more compounds of formula II, one or more compounds of formula III, one or more compounds of formula IV, and one or more chiral active substances.

[0057]

[0058]

[0059] in,

[0060] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, a fluorinated alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, a fluorinated alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, a fluorinated alkenyl group having 2-6 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms, and any one or more of the -CH2- groups shown in R1, R3, R4, and R6 may optionally be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0061] X1, X2, X3, X4, X5, and X6 each independently represent H or F;

[0062] m represents 0 or 1;

[0063] Z1, Z2, and Z3 each independently represent a single bond or -COO-;

[0064] Each represents independently

[0065] The cholesteric liquid crystal composition of the present invention preferably comprises compounds selected from those shown in Formula I-1 to Formula I-3 below.

[0066]

[0067] The cholesteric liquid crystal composition of the present invention preferably comprises compounds selected from those shown in Formula II-1 to Formula II-4.

[0068]

[0069]

[0070] The cholesteric liquid crystal composition of the present invention preferably comprises compounds selected from those shown in Formula III-1 to Formula III-14.

[0071]

[0072]

[0073] The cholesteric liquid crystal composition of the present invention preferably comprises compounds selected from those shown in Formula IV to Formula IV-4.

[0074]

[0075] in,

[0076] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, a fluorinated alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, a fluorinated alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, a fluorinated alkenyl group having 2-6 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms, and any one or more of the -CH2- groups represented by R1, R3, R4, and R6 may optionally be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0077] The cholesteric liquid crystal composition of the present invention preferably comprises one or more compounds selected from those shown in Formula I-3, one or more compounds selected from those shown in Formula II-1, II-2 or II-3, one or more compounds selected from those shown in Formula III-1, III-10 or III-11, one or more compounds selected from those shown in Formula IV-1, and one or more chiral active substances.

[0078] The cholesteric liquid crystal composition of the present invention preferably comprises at least three compounds selected from those shown in Formula I-3, at least three compounds shown in Formula II-1, at least one compound shown in Formula II-2, at least two compounds shown in Formula II-3, one or more compounds selected from those shown in Formula III-1, III-10 or III-11, at least one compound shown in Formula IV-1, and one or more chiral active substances.

[0079] Preferably, in the cholesteric liquid crystal composition of the present invention, the mass percentage of the compound represented by Formula I-3 is 35-45%, the mass percentage of the compound represented by Formula II-1 is 15-26%, the mass percentage of the compound represented by Formula II-2 is 5-15%, the mass percentage of the compound represented by Formula II-3 is 7-18%, the mass percentage of the compound represented by Formula III-1, III-10 or III-11 is 2-8%, the mass percentage of the compound represented by Formula IV-1 is 2-5%, and the chiral active substance is added based on 100% of the total content of the liquid crystal composition, with an added mass percentage of 1-7%.

[0080] The cholesteric liquid crystal composition of the present invention preferably comprises compounds of formula I-3 selected from the group consisting of compounds of formula I-3-1 to formula I-3-11.

[0081]

[0082]

[0083] The cholesteric liquid crystal composition of the present invention preferably comprises a compound of formula I-3 selected from the group consisting of compounds of formula I-3-1, I-3-5, I-3-7, and I-3-9, and more preferably comprises at least three compounds selected from the group consisting of compounds of formula I-3-1, I-3-5, I-3-7, and I-3-9.

[0084] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by Formula II-1 is selected from the group consisting of compounds represented by Formulas II-1-1 to II-1-4.

[0085]

[0086]

[0087] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by Formula II-2 is selected from the group consisting of compounds represented by Formulas II-2-1 to II-2-6.

[0088]

[0089] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the compound represented by Formula II-3 is selected from the group consisting of compounds represented by Formula II-3-1 to Formula II-3-6.

[0090]

[0091] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by Formula II-4 is selected from the group consisting of compounds represented by Formulas II-4-1 to II-4-6.

[0092]

[0093]

[0094] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by Formula IV-1 is selected from the group consisting of compounds represented by Formulas IV-1-1 to IV-1-4.

[0095]

[0096] Preferably, the cholesteric liquid crystal composition of the present invention comprises one or more compounds of formula IV-1; further, the mass percentage of the compound of formula IV-1 is not greater than 5%. Containing the compound of formula IV-1 can improve the low-temperature performance of the liquid crystal composition while exhibiting good pixel anti-jitter performance.

[0097] Preferably, in the cholesteric liquid crystal composition of the present invention, the mass percentage of the compound represented by Formula I-3 is 35-45%, the mass percentage of the compound represented by Formula II-1 is 15-26%, the mass percentage of the compound represented by Formula II-2 is 5-15%, the mass percentage of the compound represented by Formula II-3 is 7-18% and the compound represented by II-3 must contain the compound represented by Formula II-3-6, the mass percentage of the compound represented by Formula III-1, III-10 or III-11 is 2-8%, the mass percentage of the compound represented by Formula IV-1 is 2-5% and the compound represented by IV-1 must contain the compound represented by Formula IV-1-4, and the chiral active substance is added based on 100% of the total content of the liquid crystal composition, and the added mass percentage is 1-5%.

[0098] The cholesteric liquid crystal composition of the present invention preferably contains, in the case of the compound shown in formula II-3, the compound shown in formula II-3-6, and the compound shown in formula IV-1, the compound shown in formula IV-1-4. The simultaneous presence of formulas II-3-6 and IV-1-4 results in strong pixel anti-shake capability and, due to good alignment with the PI film, excellent vibration resistance.

[0099] In the cholesteric liquid crystal composition of the present invention, preferably, the aforementioned chiral active substance is selected from compounds shown in formulas S-1 to S-5 below.

[0100]

[0101] Among them, R 11 R 22 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

[0102] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula V.

[0103]

[0104] in,

[0105] R7 represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms, wherein any one or more of the -CH2- groups represented by R7 may be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0106] n represents 0 or 1.

[0107] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by formula V is selected from the group consisting of compounds represented by formulas V-1 to V-2 below.

[0108]

[0109] in,

[0110] R7 represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms, wherein any one or more of the -CH2- groups represented by R7 may be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0111] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the content of the compound represented by the aforementioned formula V is 0-9%.

[0112] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VI.

[0113]

[0114] in,

[0115] R8 and R9 each independently represent an alkyl group with 1-6 carbon atoms, an alkoxy group with 1-6 carbon atoms, or an alkenyl group with 2-6 carbon atoms;

[0116] r represents 0 or 1.

[0117] Preferably, in the cholesteric liquid crystal composition of the present invention, the compound represented by formula VI is selected from the group consisting of compounds represented by formulas VI-1 to VI-2 below.

[0118]

[0119] in,

[0120] R8 and R9 independently represent alkyl groups with 1-6 carbon atoms, alkoxy groups with 1-6 carbon atoms, or alkenyl groups with 2-6 carbon atoms.

[0121] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the content of the compound shown in Formula VI is 0-15%.

[0122] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VII.

[0123]

[0124] in,

[0125] R 10 R 11 Each can independently represent an alkyl group with 1-6 carbon atoms, an alkoxy group with 1-6 carbon atoms, or an alkenyl group with 2-6 carbon atoms;

[0126] Each represents independently

[0127] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the compound represented by formula VII is selected from the group consisting of compounds represented by formulas VII-1 to VII-3 below.

[0128]

[0129] in,

[0130] R 10 R 11 Each can be independently represented as an alkyl group with 1-6 carbon atoms, an alkoxy group with 1-6 carbon atoms, or an alkenyl group with 2-6 carbon atoms.

[0131] Preferably, the cholesteric phase liquid crystal composition of the present invention contains 0 to 3% of the compound represented by the aforementioned formula VII.

[0132] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula VIII.

[0133]

[0134] in,

[0135] R 12 R represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms. 15 Any one or more of the -CH2- groups shown may be optionally replaced by cyclopentylene, cyclobutylene, or cyclopropylene;

[0136] express

[0137] express

[0138] The cholesteric liquid crystal composition of the present invention preferably comprises compounds represented by formula VIII selected from the group consisting of compounds represented by formulas VIII-1 to VIII-5.

[0139]

[0140] in,

[0141] R 12 R represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms. 15 Any one or more of the -CH2- groups shown may be optionally replaced by cyclopentyl, cyclobutyl, or cyclopropyl.

[0142] Preferably, the cholesteric phase liquid crystal composition of the present invention contains 0 to 3% of the compound represented by the aforementioned formula VIII.

[0143] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula IX.

[0144]

[0145] in,

[0146] R 13 R 14 Each can independently represent an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms;

[0147] express

[0148] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the compound represented by formula IX is selected from the group consisting of compounds represented by formulas IX-1 to IX-4.

[0149]

[0150] in,

[0151] R 13 R 14 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

[0152] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the content of the compound represented by the aforementioned formula IX is 0-3%.

[0153] The cholesteric liquid crystal composition of the present invention preferably further comprises one or more compounds represented by formula XII.

[0154]

[0155] in,

[0156] R 15 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

[0157] Preferably, in the cholesteric phase liquid crystal composition of the present invention, the content of the compound shown in Formula XII above is 0-5%.

[0158] The cholesteric liquid crystal composition of the present invention has an ultrawide operating temperature range of -30 to 95°C, and the wavelength change at different temperatures is less than or equal to 20 nm (Δλ≤20 nm).

[0159] The compound of Formula IV of this invention exhibits good miscibility when combined with high-reliability liquid crystal monomers (containing -CF2O- and some systems containing -F), which can effectively improve the low-temperature performance of the liquid crystal composition. In addition, the cholesteric liquid crystal composition containing the compound of Formula IV has an ordered planar arrangement and high reflectivity; good focal conic astigmatism and low reflectivity; and can effectively improve the contrast of the liquid crystal composition, even by more than 50% compared with ordinary cholesteric liquid crystals on the market.

[0160] Various functional dopants can also be added to the cholesteric liquid crystal compound of the present invention. The dopants are added based on the liquid crystal composition of the present invention having a mass percentage of 100% and a mass percentage of 0.01 to 1%. Examples of such dopants include antioxidants and ultraviolet absorbers.

[0161] Antioxidants can be listed as compounds represented by formulas X-1 to X-4.

[0162]

[0163] Where t represents an integer from 1 to 10.

[0164] Light stabilizers can be listed as compounds represented by formulas XI-1 to XI-3.

[0165]

[0166]

[0167] Liquid crystal display element or liquid crystal display

[0168] The present invention also relates to a liquid crystal display element or liquid crystal display comprising any of the above-described cholesteric liquid crystal compositions; said display element or display is an active matrix display element or display or a passive matrix display element or display.

[0169] The cholesteric liquid crystal display element or cholesteric liquid crystal display of the present invention is preferably an active matrix addressing liquid crystal display element or liquid crystal display.

[0170] Liquid crystal display elements or liquid crystal displays containing the cholesteric liquid crystal composition of the present invention can operate in a wide temperature range of -30 to 95°C, have good pixel anti-jitter performance when driven in a wide temperature range, small wavelength drift in a wide temperature range, little influence of color on temperature changes, and have high charge retention rate (VHR) and excellent reliability performance.

[0171] Example

[0172] To more clearly illustrate the present invention, the following description, in conjunction with embodiments, provides further insight. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0173] Unless otherwise specified, all preparation methods in this manual are conventional, and all raw materials are available from publicly available commercial sources. Percentages refer to mass percentages, and temperatures are in degrees Celsius (°C). The specific meanings of other symbols and test conditions are as follows:

[0174] Cp represents the liquid crystal clearing point (°C), measured by DSC quantitative method;

[0175] SN represents the melting point (°C) of the crystalline to nematic phase of the liquid crystal;

[0176] Δn represents optical anisotropy, n o Let n be the refractive index of ordinary light. e The refractive index of unusual light was measured at 25±2℃, 589nm, using an Abbe refractometer.

[0177] Δε represents dielectric anisotropy, Δε = ε ∥ -ε ⊥ , where ε ∥ ε is the dielectric constant parallel to the molecular axis. ⊥ The dielectric constant is perpendicular to the molecular axis. The test conditions are 25±0.5℃, 20-micron vertical cell, and INSTEC:ALCT-IR test.

[0178] K 11 K is the elastic constant of the development. 22 The torsional elastic constant was determined under the following test conditions: 25°C, INSTEC:ALCT-IR1, and a 20-micron vertical box.

[0179] The contrast ratio test method uses a Minolta CM-2600d colorimeter to test the reflectance of the planar and focal conic states. After the sample is driven, the sample is placed for 5 minutes before testing.

[0180] Reflection wavelength test: Cholesteric liquid crystal is injected into a PI-free ITO liquid crystal cell through capillary action, and the reflection wavelength is tested using a liquid crystal comprehensive tester (DMS).

[0181] Wavelength drift test at different temperatures: Cholesteric liquid crystal was injected into a PI-free ITO liquid crystal cell through capillary action. The reflection wavelength was measured at -30℃, 25℃ and 95℃ using a liquid crystal comprehensive tester (DMS). The difference in reflection wavelength between -30℃ and 25℃ and between 25℃ and 95℃ was then calculated and compared.

[0182] Pixel jitter test method: The cholesteric liquid crystal composition is poured into a liquid crystal cell and aged at 60°C and 90% humidity for 30 days. A 25Hz square wave electrical signal is applied, and the screen is visually observed for obvious jitter.

[0183] No jitter: Grade A

[0184] Slight shaking: Grade B

[0185] Severe vibration: Grade C

[0186] LCD vehicle-mounted vibration resistance testing method: A cholesteric liquid crystal composition is filled into a liquid crystal cell. The liquid crystal device is placed on a vibration test bench and subjected to vibration tests for 22 hours under the following conditions: 10Hz (PSD=10), 100Hz (PSD=10), 300Hz (PSD=0.51), 500Hz (PSD=5), and 2000Hz (PSD=5). (Power spectral density (PSD) is an important parameter in vibration testing, describing the energy distribution of random vibration). After vibration tests at 25℃, -30℃, and 95℃, the screen brightness and contrast ratios are measured. The decrease in contrast and brightness is categorized into the following five levels:

[0187] Level 1: Brightness and contrast decrease by 5%.

[0188] Level 2: Brightness and contrast decrease by 5-10%.

[0189] Level 3: Brightness and contrast decrease by 10-20%.

[0190] Level 4: Brightness and contrast decrease by 20-40%.

[0191] Level 5: Brightness and contrast decreased by ≥40%

[0192] Among them, levels 1-3 are considered qualified, indicating that the monitor is minimally affected by vibration; levels 4-5 are considered unqualified, indicating that the monitor is significantly affected by vibration.

[0193] The cholesteric phase liquid crystal composition was filled into a liquid crystal cell and placed in constant temperature chambers at -30℃, -20℃, 80℃, 90℃ and 95℃ respectively for display operation tests.

[0194] Low-temperature preservation experiment:

[0195] Take 1g of liquid crystal composition and place it in an ampoule. Place the ampoule in a constant temperature chamber at -30℃ and observe it every 24 hours to record whether crystals precipitate. The observation period is 480 hours in total.

[0196] Take 1g of the cholesteric phase composition and place it in an ampoule. Place the ampoule in a constant temperature incubator at -20℃ and -30℃ respectively. Observe it every 24 hours and record whether crystals precipitate. Observe for a total of 480 hours.

[0197] The preparation method of the cholesteric phase liquid crystal composition is as follows: weigh each liquid crystal monomer and chiral agent according to a certain ratio and put them into a stainless steel beaker. Place the stainless steel beaker containing each liquid crystal monomer on a magnetic stirrer and heat it to melt. After most of the liquid crystal monomers in the stainless steel beaker have melted, add a magnetic rotor to the stainless steel beaker and stir the mixture evenly. After cooling to room temperature, the liquid crystal composition is obtained.

[0198] In the embodiments of the present invention, the cholesteric phase liquid crystal monomer structure is represented by code, and the code representation methods of liquid crystal ring structure, end group and linking group are shown in Table 1 and Table 2 below.

[0199] Table 1. Code table for structure

[0200]

[0201] Table 2. Correspondence codes between end groups and linking groups

[0202]

[0203] For example:

[0204]

[0205]

[0206]

[0207] Each liquid crystal monomer was weighed according to a certain ratio and placed in a stainless steel beaker. The stainless steel beaker containing each liquid crystal monomer was placed on a magnetic stirrer and heated to melt. After most of the liquid crystal monomers in the stainless steel beaker had melted, a magnetic rotor was added to the stainless steel beaker, and the mixture was stirred evenly. After cooling to room temperature, liquid crystal compositions were obtained: compositions L1 to L6 and compositions D1 to D5. The conventional performance parameters of liquid crystal compositions L1 to L6 and compositions D1 to D5 were tested using the above test method, as shown in Tables 3 and 4.

[0208] Table 3

[0209]

[0210]

[0211] Table 4

[0212]

[0213]

[0214]

[0215] One or more chiral active substances S-1 to S-5 and S811 were added to liquid crystal compositions L1 to L6 and compositions D1 to D5 to prepare cholesteric liquid crystal compositions (based on a liquid crystal composition mass percentage of 100%), namely Examples 1 to 16 and Comparative Examples 1 to 5. The reflection wavelength, operating temperature, wavelength drift Δλ from -30℃ to 25℃, wavelength drift Δλ (nm) from 25℃ to 95℃, contrast ratio, low-temperature storage at -20℃ and -30℃, pixel jitter, and shock resistance of the cholesteric liquid crystal compositions were tested, as shown in Tables 5, 6, 7, and 8.

[0216] Table 5

[0217]

[0218]

[0219] Table 6

[0220]

[0221] Table 7

[0222]

[0223] Table 8

[0224]

[0225]

[0226] Notes:

[0227] 550 a When the liquid crystal composition is heated to 95°C, it melts completely, the reflected color disappears, leaving only black, and the wavelength changes drastically.

[0228] Level 5 b The liquid crystal composition melts completely when heated to 95°C, causing the screen information to disappear and exhibiting extremely poor shock resistance.

[0229] Compared with the above comparative examples and embodiments, the liquid crystal composition of the present invention has greater optical anisotropy (Δn≥0.22), greater dielectric anisotropy, an ultra-wide operating temperature range (-30~95℃), good reliability, especially high contrast (contrast >25), small wavelength change at different temperatures (Δλ≤20nm), and the liquid crystal composition can improve the jitter problem during pixel driving of liquid crystal displays. It also has excellent shock resistance in automotive environments, especially at -30℃ and 90℃. It can be widely used in optical devices such as liquid crystal e-books, outdoor and automotive displays.

[0230] Obviously, the above embodiments disclosed in this invention are merely examples for clearly illustrating the invention, and are not intended to limit the implementation of the invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. Any obvious variations or modifications in the specification derived from the technical solutions of this invention are still within the protection scope of this invention.

Claims

1. A cholesteric liquid crystal composition, characterized in that, The cholesteric liquid crystal composition comprises one or more compounds of formula I, one or more compounds of formula II, one or more compounds of formula III, one or more compounds of formula IV, and one or more chiral active substances. in, R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, a fluorinated alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, a fluorinated alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, a fluorinated alkenyl group having 2-6 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms, and any one or more of the -CH2- groups shown in R1, R3, R4, and R6 may optionally be replaced by cyclopentylene, cyclobutylene, or cyclopropylene. X1, X2, X3, X4, X5, and X6 each independently represent H or F; m represents 0 or 1; Z1, Z2, and Z3 each independently represent a single bond or -COO-; , Each represents independently , , , , , ; The cholesteric liquid crystal composition further comprises one or more compounds represented by formula V. in, R7 represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms, wherein any one or more of the -CH2- groups represented by R7 may be replaced by cyclopentylene, cyclobutylene, or cyclopropylene. n represents 0 or 1; The cholesteric liquid crystal composition is in the temperature range The wavelength variation within the range of 30℃~25℃ and 25℃~95℃ is less than or equal to 20nm, i.e. △λ≤20nm; The contrast ratio of the cholesteric liquid crystal composition is greater than 25.

2. The cholesteric liquid crystal composition according to claim 1, characterized in that, The compound represented by Formula I is selected from the compounds represented by Formulas I-1 to I-3 below. The compound represented by Formula II is selected from the compounds represented by Formulas II-1 to II-4 below. The compound represented by Formula III is selected from the compounds represented by Formulas III-1 to III-14 below. The compound represented by Formula IV is selected from the compounds represented by Formulas IV-1 to IV-4 below. in, R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, a fluorinated alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, a fluorinated alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, a fluorinated alkenyl group having 2-6 carbon atoms, an alkenyl group having 3-8 carbon atoms, or a fluorinated alkenyl group having 3-8 carbon atoms, and any one or more of the -CH2- groups represented by R1, R3, R4, and R6 may optionally be replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

3. The cholesteric liquid crystal composition according to claim 2, characterized in that, The liquid crystal composition comprises one or more compounds selected from Formula I-3, one or more compounds selected from Formula II-1, II-2 or II-3, one or more compounds selected from Formula III-1, III-10 or III-11, one or more compounds selected from Formula IV-1, and one or more chiral active substances.

4. The cholesteric liquid crystal composition according to claim 3, characterized in that, The liquid crystal composition comprises at least three compounds selected from those shown in Formula I-3, at least three compounds shown in Formula II-1, at least one compound shown in Formula II-2, at least two compounds shown in Formula II-3, one or more compounds selected from those shown in Formula III-1, III-10 or III-11, at least one compound shown in Formula IV-1, and one or more chiral active substances.

5. The cholesteric liquid crystal composition according to claim 4, characterized in that, The liquid crystal composition contains 35-45% by mass of the compound represented by Formula I-3, 15-26% by mass of the compound represented by Formula II-1, 5-15% by mass of the compound represented by Formula II-2, 7-18% by mass of the compound represented by Formula II-3, 2-8% by mass of the compound represented by Formula III-1, III-10 or III-11, and 2-5% by mass of the compound represented by Formula IV-1. The chiral active substance is added based on the total content of the liquid crystal composition being 100%, and the added mass percentage is 1-7%.

6. The cholesteric liquid crystal composition according to any one of claims 4 or 5, characterized in that, The chiral active substance is selected from compounds shown in formulas S-1 to S-5 below. Among them, R 11 R 22 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

7. The cholesteric liquid crystal composition according to any one of claims 4 or 5, characterized in that, It also contains one or more compounds represented by formula VI. in, R8 and R9 each independently represent an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms; r represents 0 or 1.

8. The cholesteric liquid crystal composition according to claim 7, characterized in that, It also contains one or more compounds represented by formula VII. in, R 10 R 11 Each can independently represent an alkyl group with 1-6 carbon atoms, an alkoxy group with 1-6 carbon atoms, or an alkenyl group with 2-6 carbon atoms; , Each represents independently , or .

9. The cholesteric liquid crystal composition according to claim 8, characterized in that, It also includes one or more compounds represented by formula VIII. in, R 12 R represents an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms. 12 Any one or more of the -CH2- groups shown may be optionally replaced by cyclopentylene, cyclobutylene, or cyclopropylene; express , or ; express , or .

10. The cholesteric liquid crystal composition according to claim 9, characterized in that, It also contains one or more compounds represented by formula IX. in, R 13 R 14 Each can independently represent an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms; express , , or .

11. The cholesteric liquid crystal composition according to claim 10, characterized in that, It also contains one or more compounds represented by formula XII. in, R 15 Each can be independently represented as an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or an alkenyl group having 2-6 carbon atoms.

12. A cholesteric liquid crystal display element, characterized in that, The cholesteric liquid crystal composition comprising any one of claims 1-11, wherein the cholesteric liquid crystal display element is an active matrix addressing display element or a passive matrix addressing display element.

13. A cholesteric liquid crystal display, characterized in that, The cholesteric liquid crystal composition comprising any one of claims 1-11, wherein the cholesteric liquid crystal display is an active matrix addressing display or a passive matrix addressing display.

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