Liquid crystal compositions composed of pyrrole-positive liquid crystals and their applications in liquid crystal devices

Abstract

This invention discloses a liquid crystal composition composed of pyrrole-positive liquid crystals, comprising 1-80% by weight of general formula I pyrrole liquid crystals and 20%-99% by weight of general formula II liquid crystal compounds. The core of the general formula I pyrrole liquid crystal compound is a pyrrole group, which helps improve the dielectric anisotropy and response speed of the liquid crystal material. General formula II includes terminal olefin liquid crystal monomers with extremely low rotational viscosity, effectively reducing the viscosity of the liquid crystal composition and improving the response speed; it also includes polyfluorinated difluoromethoxy bridge liquid crystal monomers, which help enhance dielectric anisotropy and reduce the voltage required for liquid crystal formation; and it includes tetracyclic liquid crystal compositions, which improve the clearing point of the liquid crystal. The liquid crystal composition provides the required dielectric and optical properties, achieving high-definition clearing points above 120°C, which helps ensure the working performance of liquid crystal devices under high-temperature conditions. When applied to automotive LCOS reflective liquid crystal display devices, the response speed is improved to within 4ms.

Description

Technical Field

[0001] This disclosure relates to the field of liquid crystal display materials technology, and in particular to a liquid crystal composition composed of pyrrole-positive liquid crystal and its application in liquid crystal devices. Background Technology

[0002] In LCD display technologies such as automotive head-up displays (HUDs), traditional liquid crystal materials face significant drawbacks: their clearing point temperature range is typically between 80°C and 100°C, making them unsuitable for tropical regions or high-temperature engine compartment environments, leading to blurry or malfunctioning displays. Simultaneously, mainstream transmissive liquid crystal devices require increased cell thickness due to optical path difference requirements, resulting in response time proportional to the square of the cell thickness. This causes response delays of tens of milliseconds, resulting in ghosting during video playback and severely impacting the smoothness of dynamic scenes such as AR-HUDs. Furthermore, liquid crystal materials with high clearing points generally have high viscosity, which further degrades response speed, leading to insufficient color gamut and dull colors in automotive display products. Therefore, in the field of liquid crystal materials, there is an urgent need for a new type of liquid crystal composition with improved performance, simultaneously possessing high clearing point, low viscosity, and fast response speed. Summary of the Invention

[0003] In view of this, this patent discloses a liquid crystal composition composed of pyrrole positive liquid crystal and its application in automotive LCOS reflective liquid crystal display devices. The liquid crystal composition uses pyrrole-based monomer liquid crystal components with high anisotropic dielectric constant. Combined with fluorine-substituted benzene ring structure, it can effectively reduce viscosity and improve response speed, making it suitable for wide temperature and fast response. Combined with tetra-ring liquid crystal, it can improve the clearing point to above 120°C and optimize the response speed to within 4ms.

[0004] A first aspect of this disclosure provides a liquid crystal composition comprising a pyrrole-positive liquid crystal, the liquid crystal composition comprising: A general formula I pyrrole liquid crystal compound comprising 1-80% of the total weight of the liquid crystal composition. Formula I; Liquid crystal compounds of general formula II, comprising 20%-99% of the total weight of the liquid crystal composition. Formula II; The sum of the weight percentages of general formula I pyrrole liquid crystal compounds and general formula II liquid crystal compounds is 100%; Among them, the six-membered rings A, B, C, D, E, F, and G can represent , , or One of the following is a liquid crystal compound: a hydrogen atom (-H) on the ring can be substituted with fluorine (-F), cyano (-CN), or chlorine (-Cl); m, n, p are 0 or 1, and at least one of them is 1; q, x, y, z are 0 or 1, and at least two of them are 1 simultaneously; Z1, Z2, Z3, Z4, Z5, Z6 are bridging chains, which can be carbon single bonds, or CF2O, or (CH2O)r (r is an integer from 0, 1, 2 to 10), or (CH2)s (s is an integer from 0, 1, 2 to 10); R1, R2, R3 each independently represent a C0-C10 alkyl group, or a C0-C10 alkoxy group, or a C0-C10 alkene, or a C0-C10 mercapto group, or OCF3, or OCF2H; the sum of the weight percentages of the general formula I pyrrole liquid crystal compound and the general formula II liquid crystal compound is 100%.

[0005] The sum of the weight percentages of general formula I pyrrole liquid crystal compounds and general formula II liquid crystal compounds is 100%. Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-40% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 60-99% of the total weight of the liquid crystal composition.

[0006] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-20% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 80-99% of the total weight of the liquid crystal composition.

[0007] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-10% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 90-99% of the total weight of the liquid crystal composition.

[0008] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-5% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 95-99% of the total weight of the liquid crystal composition.

[0009] Furthermore, the general formula I pyrrole liquid crystal compound is selected from one or more compounds selected from I-1 to I-3 below: I-1; I-2; I-3.

[0010] Furthermore, the liquid crystal compound of general formula II is selected from one or more compounds of the following II-1 to II-33: II-1; II-2; II-3; II-4; II-5; II-6; II-7; II-8; II-9; II-10; II-11; II-12; II-13; II-14; II-15; II-16; II-17; II-18; II-19 II-20; II-21; II-22; II-23; II-24; II-25; II-26; II-27; II-28; II-29; II-30; II-31; II-32; II-33.

[0011] Furthermore, the liquid crystal composition is supplemented with chiral dopants, anti-photoaging agents, and antioxidants at a percentage of 0.1%-3% of the total mass of the liquid crystal composition.

[0012] The second aspect of this disclosure provides the application of the liquid crystal composition described in the first aspect in an automotive LCOS reflective liquid crystal display device, for preparing liquid crystal materials in the liquid crystal display device.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The liquid crystal composition provided by this invention comprises liquid crystal materials of two general formulas, I and II. The core of the general formula I pyrrole liquid crystal compound is a pyrrole-based liquid crystal monomer with a pyrrole group. The general formula II liquid crystal compounds include fast-response terminal olefin liquid crystal monomers, low-voltage polyfluorinated difluoromethoxy bridged liquid crystal monomers, and high-definition tetracyclic monomer liquid crystals. The pyrrole group is a highly polar heterocyclic ring, which helps to improve the dielectric anisotropy of the liquid crystal material and reduce the voltage; it also helps to improve the response speed of the liquid crystal material. The fluorinated terminal olefin molecules in the terminal olefin liquid crystal monomers have extremely low rotational viscosity, which can effectively reduce the viscosity of the liquid crystal composition and improve the response speed. For the polyfluorinated difluoromethoxy bridged liquid crystal monomers, these monomers have strong dielectric anisotropy and excellent chemical and photoelectric stability, and provide the required optical properties. The tetracyclic liquid crystal monomer helps to improve the clearing point of the liquid crystal composition. The positive liquid crystal composition composed of general formula I pyrrole liquid crystal monomers and compound II has a high-definition bright spot temperature of over 120°C, which helps to ensure the working performance of automotive LCOS reflective liquid crystal display devices under high-temperature environmental conditions. Pyrrole liquid crystals have low viscosity and fast response, making them particularly suitable for automotive LCOS reflective liquid crystal display devices, with a response speed of less than 4ms. Detailed Implementation

[0014] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0016] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0017] This invention discloses a pyrrole-positive liquid crystal composition and its application in an automotive LCOS reflective liquid crystal display device, wherein the liquid crystal composition comprises: A general formula I pyrrole liquid crystal compound comprising 1-80% of the total weight of the liquid crystal composition. Formula I; Liquid crystal compounds of general formula II, comprising 20%-99% of the total weight of the liquid crystal composition. Formula II; The sum of the weight percentages of the two components, general formula I pyrrole liquid crystal compound and general formula II liquid crystal compound, is 100%. The six-membered rings A, B, C, D, E, F, and G can represent , , or One of the following is a liquid crystal compound: a hydrogen atom (-H) on the ring can be substituted with fluorine (-F), cyano (-CN), or chlorine (-Cl); m, n, p are 0 or 1, and at least one of them is 1; q, x, y, z are 0 or 1, and at least two of them are 1 simultaneously; Z1, Z2, Z3, Z4, Z5, Z6 are bridging chains, which can be carbon single bonds, or CF2O, or (CH2O)r (r is an integer from 0, 1, 2 to 10), or (CH2)s (s is an integer from 0, 1, 2 to 10); R1, R2, R3 each independently represent a C0-C10 alkyl group, or a C0-C10 alkoxy group, or a C0-C10 alkene, or a C0-C10 mercapto group, or OCF3, or OCF2H; the sum of the weight percentages of the general formula I pyrrole liquid crystal compound and the general formula II liquid crystal compound is 100%.

[0018] Furthermore, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-40% of the total weight of the liquid crystal composition, and a liquid crystal compound of general formula II accounting for 60-99% of the total weight of the liquid crystal composition.

[0019] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-20% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 80-99% of the total weight of the liquid crystal composition.

[0020] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-10% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 90-99% of the total weight of the liquid crystal composition.

[0021] Preferably, the liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-5% of the total weight of the liquid crystal composition and a liquid crystal compound of general formula II accounting for 95-99% of the total weight of the liquid crystal composition.

[0022] Preferably, the pyrrole liquid crystal compound of general formula I is selected from one or more compounds of the following I-1 to I-3: I-1; I-2; I-3.

[0023] Preferably, the liquid crystal compound of general formula II is selected from one or more compounds of II-1 to II-33 below: II-1; II-2; II-3; II-4; II-5; II-6; II-7; II-8; II-9; II-10; II-11; II-12; II-13; II-14; II-15; II-16; II-17; II-18; II-19; II-20; II-21; II-22; II-23; II-24; II-25; II-26; II-27; II-28; II-29; II-30; II-31; II-32; II-33.

[0024] The present invention will be further illustrated below with reference to specific compound composition ratio examples.

[0025] Example 1:

[0026]

[0027]

[0028]

[0029] Example 2:

[0030]

[0031]

[0032]

[0033]

[0034] Example 3:

[0035]

[0036]

[0037]

[0038] The liquid crystal composition preparation method in the above embodiments is as follows: the above-mentioned multiple liquid crystal monomers are purified, the purified liquid crystal monomers are mixed together according to mass, and then heated while being stirred evenly with a magnetic stirrer to form a mixed liquid crystal. The mixture is then filtered and purified again with a G5 funnel to obtain a mixed liquid crystal that can be used at room temperature.

[0039] Preferably, in the formulations of Examples 1 and 2, 0.15% of a first chiral dopant is added to modulate the optical and electrical properties of the liquid crystal through the induction of a helical structure. The structural formula of the first chiral dopant is as follows:

[0040] Preferably, in Example 3, 0.1% (R / S)5011 is added to induce and stabilize the cholesteric phase and to impart a liquid crystal helical structure as a second chiral dopant. The structural formula of the second chiral dopant is as follows:

[0041] The performance tests for Examples 1 to 3 are shown in the table below: Test Project Clearing Point (°C) △n(589nm, 25℃) ne(589nm, 25℃) Δε(1kHz, 25℃) ε‖(1KHz, 25℃) ε⊥(1KHz, 25℃) V10 (V) V90 (V) T (response time in milliseconds) Example 1 120 0.13 1.641 15.4 29 13.8 2.2 4.9 3.5 Example 2 125 0.139 1.650 15.2 28 13 2.3 5.0 3.9 Example 3 122 0.138 1.646 16 30 14 2.1 4.8 3.8 As shown in the table above, the liquid crystal composition materials in Examples 1 to 3 exhibit superior thermal stability (Clearing Point), optical properties (Δn, ne), electrical properties (Δε, ε‖, ε⊥), and key electro-optical properties (threshold voltage, response time) in practical display applications. The Clearing Point of the three examples exceeds 120°C, demonstrating a wider operating temperature range and superior thermal stability compared to existing liquid crystal materials. The refractive index anisotropy of the liquid crystal for ordinary and extraordinary light was measured at 589 nm wavelength and 25°C, with Δn ranging from 0.130 to 0.139. A lower Δn is beneficial for improving viewing angle characteristics and reducing color shift. Δε, measured at 1 kHz frequency and 25°C, reflects the difference in dielectric constant between the liquid crystal molecules parallel (ε‖) and perpendicular (ε⊥) to the long axis direction. This is a key parameter determining the responsiveness of liquid crystal molecules in an electric field, influencing the driving voltage and response speed. In this embodiment, Δε ranges from 15.2 to 16.0, exhibiting high dielectric anisotropy, meaning the liquid crystal molecules are highly sensitive to the electric field. The threshold voltage, V10, refers to the voltage required for the transmittance to reach 10% of its maximum value, the voltage at which the liquid crystal begins to respond; V90 refers to the voltage required for the transmittance to reach 90% of its maximum value, the voltage at which the liquid crystal is nearly fully turned on. Both define the voltage operating window for driving the liquid crystal. In this implementation, V10 is between 2.1 and 2.3V, which is lower than the traditional 3V or higher, thus reducing power consumption. Response speed refers to the time required for the liquid crystal to change state (e.g., from dark to bright) under the influence of an electric field. In the above embodiment, the tested response speed is 3.5-3.9ms, exhibiting a fast response speed and effectively solving the problem of image ghosting.

[0042] The pyrrole positive liquid crystal composition described above is applied to automotive LCOS reflective liquid crystal display devices, enabling the automotive LCOS reflective liquid crystal display devices to have high-definition bright spots at 120°C while having a response speed of less than 4ms, meeting the requirements for normal use in high-temperature environments.

[0043] The parts not described in detail in this technical solution specification are obvious to those skilled in the art and can be supplemented and improved based on existing technical knowledge. At the same time, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the present invention. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A liquid crystal composition consisting of a pyrrole-positive liquid crystal, characterized in that, The liquid crystal composition includes the following compounds: (1) A general formula I pyrrole liquid crystal compound comprising 1-80% of the total weight of the liquid crystal composition. Formula I; (2) Liquid crystal compounds of general formula II, comprising 20%-99% of the total weight of the liquid crystal composition. Formula II; in The pyrrole group; the six-membered rings A, B, C, D, E, F, and G can represent , , or One of the following is a liquid crystal compound: a hydrogen atom (-H) on the ring can be substituted with fluorine (-F), cyano (-CN), or chlorine (-Cl); m, n, p are 0 or 1, and at least one of them is 1; q, x, y, z are 0 or 1, and at least two of them are 1 simultaneously; Z1, Z2, Z3, Z4, Z5, Z6 are bridging chains, which can be carbon single bonds, or CF2O, or (CH2O)r (r is an integer from 0, 1, 2 to 10), or (CH2)s (s is an integer from 0, 1, 2 to 10); R1, R2, R3 each independently represent a C0-C10 alkyl group, or a C0-C10 alkoxy group, or a C0-C10 alkene, or a C0-C10 mercapto group, or OCF3, or OCF2H; the sum of the weight percentages of the general formula I pyrrole liquid crystal compound and the general formula II liquid crystal compound is 100%.

2. The liquid crystal composition according to claim 1, characterized in that... The liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-40% of the total weight of the liquid crystal composition, and a liquid crystal compound of general formula II accounting for 60-99% of the total weight of the liquid crystal composition.

3. The liquid crystal composition according to claim 1, characterized in that, The liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-20% of the total weight of the liquid crystal composition, and a liquid crystal compound of general formula II accounting for 80-99% of the total weight of the liquid crystal composition.

4. The liquid crystal composition according to claim 1, characterized in that, The liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-10% of the total weight of the liquid crystal composition, and a liquid crystal compound of general formula II accounting for 90-99% of the total weight of the liquid crystal composition.

5. The liquid crystal composition according to claim 1, characterized in that, The liquid crystal composition comprises a pyrrole liquid crystal compound of general formula I accounting for 1-5% of the total weight of the liquid crystal composition, and a liquid crystal compound of general formula II accounting for 95-99% of the total weight of the liquid crystal composition.

6. The liquid crystal composition according to claim 1, characterized in that, The general formula I pyrrole liquid crystal compound is selected from one or more compounds of the following I-1 to I-3: I-1； I-2； I-3。 7. The liquid crystal composition according to claim 1, characterized in that, The liquid crystal compound of general formula II is selected from one or more compounds of the following II-1 to II-33: Ⅱ-1； Ⅱ-2； Ⅱ-3； Ⅱ-4； Ⅱ-5； Ⅱ-6； Ⅱ-7； Ⅱ-8； Ⅱ-9； Ⅱ-10； Ⅱ-11； Ⅱ-12； Ⅱ-13； Ⅱ-14； Ⅱ-15； Ⅱ-16； Ⅱ-17； Ⅱ-18； Ⅱ-19； Ⅱ-20； Ⅱ-21； Ⅱ-22； Ⅱ-23； Ⅱ-24； Ⅱ-25； Ⅱ-26； Ⅱ-27； Ⅱ-28； Ⅱ-29； Ⅱ-30； Ⅱ-31； Ⅱ-32； Ⅱ-33。 8. The liquid crystal composition according to claim 1, characterized in that, The additives in the liquid crystal composition are chiral dopants, photoaging inhibitors, and antioxidants, comprising 0.1%-3% of the total mass of the liquid crystal composition.

9. The application of the liquid crystal composition consisting of a pyrrole-positive liquid crystal according to any one of claims 1-8 in a liquid crystal device, characterized in that, The liquid crystal composition is used to prepare liquid crystal display devices.

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