Fluorinated Liquid Crystal Compound for Wide Temperature Range
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Solution Overview
Problem
Current liquid crystal display devices face challenges in achieving a high maximum temperature of the nematic phase, low minimum temperature, small viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, high stability to ultraviolet light and heat, and long service life, which are essential for improving their performance and durability.
Innovation Solution
A compound represented by formula (1) is introduced, which is incorporated into a liquid crystal composition to enhance the alignment of liquid crystal molecules, improve solubility, and maintain chemical stability, thereby optimizing the composition's characteristics for use in liquid crystal display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional liquid crystal compositions are used, then the device can operate, but the maximum temperature of the nematic phase is limited and the service life is shortened due to poor stability
Solution Approach 1:
The patent modifies the molecular structure of liquid crystal compounds by introducing fluorine atoms at specific positions (using parameters a, b, c, d, e, f, g, h, i, j, k, l, m, n, p, q, r, s, t, u, v, w, x, y, z to control the number and position of fluorine atoms). This chemical parameter change enhances the stability to ultraviolet light and heat while extending the nematic phase temperature range, resolving the contradiction between temperature performance and stability.
Solution Approach 2:
The patent creates a composite liquid crystal composition by combining multiple compounds with specific fluorine-containing structures (Formula 1 and Formula 2 compounds) in defined weight ratios. This composite approach synergistically improves both the maximum nematic phase temperature and the stability to environmental factors like UV light and heat, achieving enhanced reliability without sacrificing temperature performance.
2Temperature
If the liquid crystal composition is optimized for high temperature performance, then the maximum temperature increases, but the viscosity may increase leading to longer response time
Solution Approach 1:
The patent carefully controls the fluorine atom configuration (using parameters a through z) to achieve an optimal balance between molecular packing (affecting temperature range) and molecular mobility (affecting viscosity). By adjusting the number and position of fluorine atoms, the composition achieves high maximum nematic phase temperature while maintaining low viscosity for fast response time.
Solution Approach 2:
The patent introduces fluorine atoms at specific local positions within the molecular structure (different positions indicated by different parameter combinations) to create local regions with optimized properties. This localized modification allows different parts of the molecular structure to contribute differently to temperature stability and viscosity, resolving the contradiction between high-temperature performance and fast response.
3Ease of manufacture
If the liquid crystal composition uses simple molecular structures, then the manufacturing is easier, but the optical anisotropy and dielectric anisotropy are insufficient
Solution Approach 1:
The patent uses a systematic parameter approach (a through z) to control the complexity of fluorine atom arrangement. By adjusting these parameters, the synthesis complexity can be controlled while maintaining or enhancing optical and dielectric anisotropy. This allows optimization between manufacturing ease and performance precision.
Solution Approach 2:
The patent employs homologous series of fluorine-containing compounds (Formula 1 and Formula 2) with systematic variations in fluorine atom positions and numbers. This homogeneous structural approach allows for scalable synthesis while maintaining consistent high optical and dielectric anisotropy properties, resolving the contradiction between manufacturing simplicity and performance precision.
4Speed
If the liquid crystal composition is optimized for fast response time, then the viscosity is reduced, but the temperature range of the nematic phase narrows
Solution Approach 1:
The patent adjusts the fluorine atom configuration parameters (a through z) to simultaneously optimize molecular mobility (for fast response) and thermal stability (for wide temperature range). The specific fluorine positioning creates a balance where low viscosity is achieved without sacrificing the maximum nematic phase temperature.
Solution Approach 2:
The patent combines multiple fluorine-containing liquid crystal compounds (Formula 1 and Formula 2) in specific ratios to create a composite composition. This composite approach allows different components to contribute differently to viscosity and temperature range, achieving fast response time while maintaining a wide operational temperature range that would be difficult to achieve with single compounds.
Data Source
AI summary
A polar compound has a high chemical stability, high ability to align liquid crystal molecules and high solubility in a liquid crystal composition, and causes no decrease of liquid crystallinity of the liquid crystal composition, a liquid crystal composition contains the compound, and a liquid crystal display device includes the composition.The compound is represented by formula (1), the composition contains the compound, and the liquid crystal display device uses the composition.In formula (1), R1 is alkyl having 3 to 15 carbons, alkenyl having 4 to 15 carbons or the like; a is an integer from 2 to 12; and R2 is a group represented by formula (1a), formula (1b) or formula (1c).In the formulas, S1 and S2 are independently a single bond, alkylene having 1 to 10 carbons; S3 is >CH— or >N—; S4 is >C< or >Si<; and X1 is —OH, —NH2 or the like.