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

Abstract

The invention discloses a cholesteric liquid crystal composition. The liquid crystal composition contains one or more compounds as shown in a formula I, one or more compounds as shown in a formula II, one or more compounds as shown in a formula III, one or more compounds as shown in a formula IV and one or more chiral active substances. The liquid crystal composition provided by the invention has relatively large optical anisotropy (delta n is greater than or equal to 0.22), relatively large dielectric anisotropy, ultra-wide working temperature range (-30 to 95 DEG C), good reliability, especially high contrast ratio (contrast ratio is greater than 25), and small wavelength change (lambda is less than or equal to 20nm) at different temperatures. And the liquid crystal composition can improve poor shaking of a liquid crystal display, has excellent anti-vibration performance in a vehicle-mounted environment, and particularly has good anti-vibration performance at-30 DEG C and 90 DEG C. The liquid crystal display can be widely applied to optical devices such as liquid crystal electronic books, outdoor and vehicle-mounted displays and the like. # imgabs0 #

Description

Technical Field

[0001] The invention relates to a cholesteric liquid crystal composition and a liquid crystal display element or a liquid crystal display using the same, which is mainly applicable to the technical fields of liquid crystal electronic books, electronic signs, bistable liquid crystal displays and the like. Background Art

[0002] Cholesteric liquid crystal electronic books have the advantages of high contrast and zero power consumption for displaying content. They can replace paper in daily life and are mainly used in electronic books, electronic labels, display panels, etc. Cholesteric liquid crystal compositions are obtained by adding optically active chiral agents to nematic liquid crystals. The planar state and focal conic state of cholesteric liquid crystals are stable and can remain stable for a long time, thus having bistability.

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

[0004] At present, the operating temperature range of cholesteric liquid crystals on the market is generally -20 to 70°C, and the operating temperature range of electronic inks is generally -20 to 60°C. The operating temperature range of mainstream cholesteric liquid crystal display technology cannot open a significant gap with electronic ink display technology. In an environment where electronic ink e-books dominate the mainstream market, cholesteric liquid crystals cannot surpass the operating temperature and width performance of electronic inks to compete for the market. In addition, when the reflection wavelength of cholesteric liquid crystal compositions changes greatly at different temperatures, it will cause RGB color drift, resulting in distortion of the color display of cholesteric liquid crystals. Moreover, the driving voltage is different at different temperatures, the driving voltage is high at low temperatures, and the driving voltage is low at high temperatures. The high and low temperature driving voltage difference ΔV>15V makes the driving circuit design complicated and the circuit cost high. Therefore, a reasonably designed liquid crystal type formula can reduce the amplitude of the high and low temperature voltage difference.

[0005] Electronic ink electronic paper uses black and white charged particles as display media. The black and white charged particles in the electronic ink screen capsule move under the action of the electric field. After the power is removed, the black and white ball state is maintained, thus forming a display. In the vehicle environment, due to the accumulation of road vibration and engine vibration, continuous vibration will cause a small amount of precipitation of black and white ball particles, and the handwriting in the electronic ink screen display area will fade or even disappear. Liquid crystal relies on interface and polymer stabilization and has more anti-seismic advantages. Reasonable design of cholesteric liquid crystal can make cholesteric liquid crystal electronic paper have better anti-seismic performance in high and low temperature environments.

[0006] The cholesteric liquid crystal used in electronic paper generally has a relatively large dielectric constant. After aging, long-term operation or high-temperature operation, the liquid crystal composition with a large dielectric constant is prone to release ions in the liquid crystal composition or glass, and the polar liquid crystal molecules are prone to adsorb these ions. In addition, cholesteric liquid crystals are generally driven at a low frequency. Under low-frequency driving, the continuous disturbance of ions released from the liquid crystal composition or glass will cause the liquid crystal molecules to be unstable, and the pixels of the device will continuously shake, which is unacceptable to consumers.

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

[0008] The present invention provides a new technical solution, which can solve the above technical problems.

[0009] The liquid crystal composition of the present invention has large optical anisotropy (Δn≥0.22), large dielectric anisotropy, ultra-wide operating temperature range (-30 to 95°C), good reliability, especially high contrast (contrast>25), small wavelength change at different temperatures (Δλ≤20nm), and the liquid crystal composition can improve the poor jitter of liquid crystal displays, and can have excellent anti-vibration performance in a vehicle environment, especially good anti-vibration performance at -30°C and 90°C. It can be widely used in optical device fields such as wide-temperature liquid crystal e-books, outdoor and vehicle-mounted liquid crystal displays with strict requirements on wide temperatures, etc.

[0010] Specifically, the present invention provides a cholesteric liquid crystal composition, which 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.

[0011]

[0012] in,

[0013] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1, R3, R4, and R6 are optionally 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 independently expresses

[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 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and any one or more -CH2- in the group represented by R7 is optionally replaced by a cyclopentylene, a cyclobutylene, or a cyclopropylene group;

[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 having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 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 independently represents F, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms;

[0032] Each independently expresses

[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 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R 12 Any one or more -CH2- in the groups shown are 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 independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 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 independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0048] The cholesteric liquid crystal composition of the present invention preferably has an ultra-wide operating temperature range of -30 to 95° C., and the wavelength variation at different temperatures is less than or equal to 20 nm, that is, 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 vehicle-mounted displays, etc.

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

[0052] Effects of the Invention

[0053] The liquid crystal composition of the present invention has large optical anisotropy (Δn≥0.22), large dielectric anisotropy, ultra-wide operating temperature range (-30 to 95°C), good reliability, especially high contrast (contrast>25), small wavelength change at different temperatures (Δλ≤20nm), and the liquid crystal composition can improve the poor jitter during pixel driving of the liquid crystal display. At the same time, the liquid crystal composition of the present invention has good alignment force with the PI film, so it can have excellent anti-vibration performance in a vehicle environment, especially good anti-vibration performance at -30°C and 90°C. It can be widely used in optical devices such as liquid crystal electronic books, outdoor and vehicle-mounted displays. DETAILED DESCRIPTION

[0054] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0055] Liquid crystal composition

[0056] The present invention provides a cholesteric liquid crystal composition, which 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.

[0057]

[0058]

[0059] in,

[0060] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1, R3, R4, and R6 are optionally 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 independently expresses

[0065] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula I is selected from the compounds represented by the following formulas I-1 to I-3,

[0066]

[0067] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II is selected from the compounds represented by the following formula II-1 to formula II-4,

[0068]

[0069]

[0070] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula III is selected from the compounds represented by the following formulas III-1 to III-14,

[0071]

[0072]

[0073] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IV is selected from the compounds represented by the following formulas IV-1 to IV-4,

[0074]

[0075] in,

[0076] R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, an alkyl group having 1-6 carbon atoms substituted with fluorine, an alkoxy group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms substituted with fluorine, an alkenyl group having 2-6 carbon atoms, an alkenyl group having 2-6 carbon atoms substituted with fluorine, an alkenyloxy group having 3-8 carbon atoms, or an alkenyloxy group having 3-8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1, R3, R4, and R6 are optionally replaced by cyclopentylene, cyclobutylene, or cyclopropylene.

[0077] The cholesteric liquid crystal composition described in the present invention, preferably, the aforementioned liquid crystal composition contains 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.

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

[0079] The cholesteric liquid crystal composition described in the present invention is preferably such that the mass percentage of the compound represented by formula I-3 in the aforementioned liquid crystal composition 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 amount of chiral active substance added is 1-7% on the basis of 100% of the total content of the liquid crystal composition.

[0080] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula I-3 is selected from the group consisting of the compounds represented by the following formula I-3-1 to the compounds represented by the following formula I-3-11,

[0081]

[0082]

[0083] The cholesteric liquid crystal composition described in the present invention is preferably composed of the compound represented by the aforementioned formula Ⅰ-3 selected from the group consisting of compounds represented by formula Ⅰ-3-1, Ⅰ-3-5, Ⅰ-3-7, and Ⅰ-3-9, and is further preferably composed of at least three compounds selected from the group consisting of compounds represented by formula Ⅰ-3-1, Ⅰ-3-5, Ⅰ-3-7, and Ⅰ-3-9.

[0084] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II-1 is selected from the group consisting of compounds represented by the following formulas II-1-1 to II-1-4,

[0085]

[0086]

[0087] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II-2 is selected from the group consisting of the compounds represented by the following formulas II-2-1 to II-2-6,

[0088]

[0089] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II-3 is selected from the group consisting of the compounds represented by the following formulas II-3-1 to II-3-6,

[0090]

[0091] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II-4 is selected from the group consisting of the compounds represented by the following formulae II-4-1 to II-4-6,

[0092]

[0093]

[0094] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IV-1 is selected from the group consisting of compounds represented by the following formulae IV-1-1 to IV-1-4,

[0095]

[0096] The cholesteric liquid crystal composition of the present invention preferably 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%. The compound of formula IV-1 can improve the low temperature performance of the liquid crystal composition while having good pixel anti-jitter performance.

[0097] The cholesteric liquid crystal composition of the present invention is preferably such that the mass percentage of the compound represented by formula I-3 in the aforementioned liquid crystal composition 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 formula 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 amount of chiral active substance added is added on the basis of 100% of the total content of the liquid crystal composition, and the added mass percentage is 1-5%.

[0098] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II-3 must contain the compound represented by the formula II-3-6, and the compound represented by the formula IV-1 must contain the compound represented by the formula IV-1-4. The simultaneous presence of formula II-3-6 and formula IV-1-4 can provide a relatively strong pixel anti-shake capability and good anti-vibration capability due to the good alignment force with the PI film.

[0099] In the cholesteric liquid crystal composition of the present invention, preferably, the chiral active substance is selected from the compounds represented by the following formulas S-1 to S-5:

[0100]

[0101] Among them, R 11 , R 22 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 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 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and any one or more -CH2- in the group represented by R7 is optionally replaced by a cyclopentylene, a cyclobutylene, or a cyclopropylene group;

[0106] n represents 0 or 1.

[0107] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula V is selected from the group consisting of the compounds represented by the following formulas V-1 to V-2,

[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, and any one or more -CH2- in the group represented by R7 can be optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene.

[0111] In the cholesteric liquid crystal composition of the present invention, preferably, 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 having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms;

[0116] r represents 0 or 1.

[0117] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula VI is selected from the group consisting of the compounds represented by the following formulas VI-1 to VI-2,

[0118]

[0119] in,

[0120] R8 and R9 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0121] In the cholesteric liquid crystal composition of the present invention, preferably, the content of the compound represented by the above 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 independently represents F having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms;

[0126] Each independently expresses

[0127] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula VII is selected from the group consisting of the compounds represented by the following formulae VII-1 to VII-3,

[0128]

[0129] in,

[0130] R 10 , R 11 Each independently represents F having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0131] In the cholesteric liquid crystal composition of the present invention, preferably, the content of the compound represented by the above formula VII is 0-3%.

[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 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R 15 Any one or more -CH2- in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene;

[0136] express

[0137] express

[0138] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the previous formula VIII is selected from the group consisting of the compounds represented by the following formulas VIII-1 to VIII-5,

[0139]

[0140] in,

[0141] R 12 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R 15 Any one or more -CH2- groups in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene.

[0142] In the cholesteric liquid crystal composition of the present invention, preferably, the content of the compound represented by the aforementioned formula VIII is 0-3%.

[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 independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms;

[0147] express

[0148] In the cholesteric liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IX is selected from the group consisting of compounds represented by the following formulas IX-1 to IX-4,

[0149]

[0150] in,

[0151] R 13 , R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0152] In the cholesteric liquid crystal composition of the present invention, preferably, the content of the compound represented by the above 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 independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0157] In the cholesteric liquid crystal composition of the present invention, preferably, the content of the compound represented by the above formula XII is 0-5%.

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

[0159] The compound represented by formula IV of the present invention has good miscibility when combined with high-reliability liquid crystal monomers (containing -CF2O- and some -F systems), and can effectively improve the low temperature of the liquid crystal composition; in addition, the cholesteric liquid crystal composition containing the compound represented by formula IV has an orderly planar arrangement and high reflectivity; the focal conic state has good astigmatism and low reflectivity; and can effectively improve the contrast of the liquid crystal composition, which is even more than 50% higher than the contrast of ordinary cholesteric liquid crystals on the market.

[0160] Various functional dopants may be added to the cholesteric liquid crystal compound of the present invention. The dopants are added on the basis of 100% by mass of the liquid crystal composition of the present invention. The mass percentage of the dopants is 0.01-1%. These dopants include, for example, antioxidants and ultraviolet absorbers.

[0161] Examples of the antioxidant include compounds represented by formula X-1 to formula X-4,

[0162]

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

[0164] The light stabilizer may include compounds represented by formula XI-1 to formula 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 a liquid crystal display comprising any one of the above-mentioned cholesteric liquid crystal compositions; the display element or the display is an active matrix display element or the display or a passive matrix display element or the display.

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

[0170] The liquid crystal display element or liquid crystal display comprising the cholesteric liquid crystal composition of the present invention can operate at a wide temperature range of -30 to 95°C, has good pixel anti-jitter performance when driven at a wide temperature range, has small wavelength drift at a wide temperature range, has little color impact by temperature changes, has a high charge retention rate (VHR), and has excellent reliability performance.

[0171] Example

[0172] In order to explain the present invention more clearly, the present invention is further described below in conjunction with embodiments. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0173] In this specification, unless otherwise specified, the preparation methods are conventional methods, the raw materials used are available from public commercial channels unless otherwise specified, the percentages are mass percentages, the temperatures are degrees Celsius (℃), and the specific meanings of other symbols and test conditions are as follows:

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

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

[0176] Δn represents the optical anisotropy, n o is the refractive index of ordinary light, n e It is the refractive index of extraordinary light, tested at 25±2℃, 589nm, and Abbe refractometer.

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

[0178] K 11 is the splay elastic constant, K 22 is the torsional elastic constant, the test conditions are: 25°C, INSTEC:ALCT-IR1, 20 μm vertical box;

[0179] Contrast test method: use Minolta CM-2600d colorimeter to test the reflectivity in planar state and focal conic state. After the sample is driven, let it stand for 5 minutes before testing again.

[0180] Reflection wavelength test: Cholesteric liquid crystal is poured into the ITO liquid crystal box without PI by capillary action, and the reflection wavelength is tested using a liquid crystal comprehensive tester (DMS);

[0181] Reflection wavelength drift test at different temperatures: Cholesteric liquid crystal is infused into a PI-free ITO liquid crystal box through capillary action, and the reflection wavelength is tested at -30℃, 25℃ and 95℃ using a liquid crystal comprehensive tester (DMS), and then the reflection wavelength difference at -30℃~25℃ and 25℃~95℃ is calculated and compared;

[0182] Pixel jitter test method: The cholesteric liquid crystal composition is poured into the liquid crystal box and aged for 30 days at 60°C and 90% humidity. A 25Hz square wave electrical signal is applied and the screen is observed with the naked eye to see if there is obvious jitter:

[0183] No jitter: Class A

[0184] Slight shaking: Grade B

[0185] Severe jitter: Grade C

[0186] Liquid crystal vehicle vibration test method: The cholesteric liquid crystal composition is poured into the liquid crystal box, and the liquid crystal device is placed on the vibration test bench. The vibration test is conducted for 22 hours using the experimental conditions of 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 for vibration testing, which describes the energy distribution of random vibrations). The screen brightness and contrast values ​​are tested after vibrations at 25℃, -30℃, and 95℃, and are divided into the following 5 levels according to the contrast and brightness reduction:

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

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

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

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

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

[0192] Among them, 1-3 levels are qualified, and the display is slightly affected by vibration; 4-5 levels are unqualified, and the display is greatly affected by vibration;

[0193] The cholesteric liquid crystal composition is poured into a liquid crystal box, and placed in a constant temperature box at -30°C, -20°C, 80°C, 90°C and 95°C for display operation test;

[0194] Cryopreservation experiment:

[0195] 1 g of the liquid crystal composition was taken and placed in an ampoule bottle, which was placed in a constant temperature box at -30°C. The ampoule bottles were observed every 24 hours to record whether crystals were precipitated. The total observation time was 480 hours.

[0196] 1 g of the cholesteric phase composition was taken and placed in an ampoule bottle, and placed in a constant temperature box at -20°C and -30°C, respectively. The ampoule was observed every 24 hours to record whether crystals were precipitated. The total observation time was 480 hours.

[0197] The preparation method of the cholesteric liquid crystal composition is as follows: each liquid crystal monomer and a chiral agent are weighed according to a certain ratio and put into a stainless steel beaker, and the stainless steel beaker containing each liquid crystal monomer is placed on a magnetic stirring instrument to heat and melt. After most of the liquid crystal monomers in the stainless steel beaker are melted, a magnetic rotor is added to the stainless steel beaker, and the mixture is stirred evenly. After cooling to room temperature, a liquid crystal composition is obtained.

[0198] The cholesteric liquid crystal monomer structure of the embodiment of the present invention is represented by a code, and the code representation method of the liquid crystal ring structure, end group, and connecting group is shown in Table 1 and Table 2 below.

[0199] Table 1 Structure code table

[0200]

[0201] Table 2 Corresponding codes of terminal groups and linking groups

[0202]

[0203] Example:

[0204]

[0205]

[0206]

[0207] Each liquid crystal monomer is weighed according to a certain ratio and put into a stainless steel beaker. The stainless steel beaker containing each liquid crystal monomer is placed on a magnetic stirring instrument to heat and melt. After most of the liquid crystal monomers in the stainless steel beaker are melted, a magnetic rotor is added to the stainless steel beaker, and the mixture is stirred evenly. After cooling to room temperature, liquid crystal compositions are 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 are tested by the above test method, as shown in Table 3 and Table 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 are added to the liquid crystal compositions L1 to L6 and the compositions D1 to D5 to form cholesteric liquid crystal compositions (wherein the mass percentage of the liquid crystal composition is 100%), namely, Examples 1 to 16 and Comparative Examples 1 to 5. The reflection wavelength, operating temperature, wavelength drift Δλ from -30°C to 25°C, wavelength drift Δλ (nm) from 25°C to 95°C, contrast, low temperature storage at -20°C and -30°C, pixel jitter and anti-vibration effects of the cholesteric liquid crystal compositions are 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 completely melts, the reflected color disappears, only black is left, and the wavelength changes greatly.

[0228] Level 5 b : The liquid crystal composition completely melts when heated to 95°C, the screen information disappears, and the anti-vibration effect is extremely poor.

[0229] By comparing the comparative examples with the embodiments, the liquid crystal composition of the present invention has a larger optical anisotropy (Δn≥0.22), a larger dielectric anisotropy, an ultra-wide operating temperature range (-30 to 95°C), 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 the pixel drive of the liquid crystal display and have excellent shock resistance in a vehicle environment, especially good shock resistance at -30°C and 90°C, and can be widely used in optical devices such as liquid crystal e-books, outdoor and vehicle-mounted displays.

[0230] Obviously, the above embodiments disclosed in the present invention are only examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications in the specification derived from the technical solution of the present invention are still within the protection scope of the present 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 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with fluorine, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms substituted with fluorine, an alkenyl group having 2 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms substituted with fluorine, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1, R3, R4, and R6 are optionally 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 independently expresses 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 the following formulas I-1 to I-3, The compound represented by formula II is selected from the compounds represented by the following formulas II-1 to II-4, The compound represented by formula III is selected from the compounds represented by the following formulas III-1 to III-14, The compound represented by formula IV is selected from the compounds represented by the following formulas IV-1 to IV-4, in, R1, R2, R3, R4, R5, and R6 each independently represent an alkyl group having 1-6 carbon atoms, an alkyl group having 1-6 carbon atoms substituted with fluorine, an alkoxy group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms substituted with fluorine, an alkenyl group having 2-6 carbon atoms, an alkenyl group having 2-6 carbon atoms substituted with fluorine, an alkenyloxy group having 3-8 carbon atoms, or an alkenyloxy group having 3-8 carbon atoms substituted with fluorine, and any one or more -CH2- groups represented by R1, R3, R4, and R6 are optionally 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 formula I-3, at least three compounds of formula II-1, at least one compound of formula II-2, at least two compounds of formula II-3, one or more compounds selected from formula III-1, III-10 or III-11, at least one compound of formula IV-1 and one or more chiral active substances.

5. The cholesteric liquid crystal composition according to claim 4, characterized in that: The mass percentage of the compound represented by formula I-3 in the liquid crystal composition 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 amount of chiral active substance added is 1-7% on the basis of 100% of the total content of the liquid crystal composition.

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 the compounds represented by the following formulas S-1 to S-5, Among them, R 11 , R 22 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

7. The cholesteric liquid crystal composition according to any one of claims 4 or 5, characterized in that: The cholesteric liquid crystal composition further comprises one or more compounds represented by formula V, in, R7 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and any one or more -CH2- in the group represented by R7 is optionally replaced by a cyclopentylene, a cyclobutylene, or a cyclopropylene group; n 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 VI, in, R8 and R9 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms; r represents 0 or 1.

9. The cholesteric liquid crystal composition according to claim 8, characterized in that: It also contains one or more compounds represented by formula VII, in, R 10 , R 11 Each independently represents F having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms; Each independently expresses 10. The cholesteric liquid crystal composition according to claim 9, characterized in that: It also contains one or more compounds represented by formula VIII, in, R 12 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R 12 Any one or more -CH2- in the groups shown are optionally replaced by cyclopentylene, cyclobutylene or cyclopropylene; express express 11. The cholesteric liquid crystal composition according to claim 10, characterized in that: Also comprising one or more compounds of formula IX, in, R 13 , R 14 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms; express 12. The cholesteric liquid crystal composition according to claim 11, characterized in that: Also comprising one or more compounds of formula XII, in, R 15 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

13. A cholesteric liquid crystal composition according to any one of claims 1 to 12, characterized in that: The wavelength variation of the cholesteric liquid crystal composition at different temperatures is less than or equal to 20 nm, that is, Δλ≤20 nm.

14. A cholesteric liquid crystal composition according to any one of claims 1 to 12, characterized in that: The contrast ratio of the cholesteric liquid crystal composition is greater than 25.

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

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

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