Fluorinated Liquid Crystal Compound for Display Device Performance
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Solution Overview
Problem
Current liquid crystal compounds for display devices, particularly those with negative dielectric anisotropy, often fall short in achieving a balance of high stability, low viscosity, large negative dielectric anisotropy, and suitable elastic constants, which limits their performance in improving viewing angle, response time, and power consumption.
Innovation Solution
A liquid crystal compound represented by a specific formula with an alkyloxy or alkyleneoxy skeleton, featuring a negative dielectric anisotropy, is developed, which includes various substituents and linkages that enhance its physical properties such as stability, clearing point, and optical anisotropy, allowing for improved compatibility with other compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid crystal compounds with negative dielectric anisotropy are used to improve viewing angle characteristics, then device performance in IPS/VA modes is improved, but the compounds often fail to achieve a balance of high stability, low viscosity, large negative dielectric anisotropy, and suitable elastic constants
Solution Approach 1:
The patent systematically modifies molecular parameters including the introduction of fluorine atoms at specific positions (2,3-difluoro-1,4-phenylene structure), adjustment of alkyl chain lengths (C1-C6), modification of linkage types (single bond, double bond, triple bond), and variation of substituent groups (halogen, cyano, carbonyl) to achieve optimal balance across multiple physical properties simultaneously
Solution Approach 2:
The invention creates composite molecular structures combining multiple functional units: fluorinated phenylene cores provide dielectric anisotropy, alkyl chains contribute to viscosity control, and various substituents (cyano, carbonyl, halogen) adjust elastic constants and stability, achieving a synergistic balance of properties
2Productivity
If existing liquid crystal compounds are used, then device operation is maintained, but response time is insufficient and threshold voltage is too high
Solution Approach 1:
The patent achieves faster response times and lower threshold voltages by changing molecular parameters: introducing fluorine atoms increases dielectric anisotropy (lowering threshold voltage), adjusting alkyl chain lengths optimizes viscosity (controlling response time), and modifying substituent groups fine-tunes elastic constants for optimal device performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compound achieves a wide temperature range, short response time, low threshold voltage, high contrast ratio, and extended service life in liquid crystal display devices, addressing the limitations of existing compounds by providing a balanced set of physical properties.
Implementation Method 1
a liquid crystal compound having a negative dielectric anisotropy
Implementation Method 2
utilizes optical anisotropy, dielectric anisotropy and so forth of a liquid crystal compound
Data Source
AI summary
To provide a liquid crystal compound satisfying at least one of physical properties such as a high stability to heat, light and so forth, a high clearing point, a low minimum temperature of a liquid crystal phase, a small viscosity, a suitable optical anisotropy, a large dielectric anisotropy, a suitable elastic constant and an excellent compatibility with other liquid crystal compounds; a liquid crystal composition containing the compound; and a liquid crystal display device including the composition. The compound is represented by formula (1):wherein, for example, Ra and Rb are alkyl having 1 to 10 carbons, alkenyl having 2 to 10 carbons or alkoxy having 1 to 9 carbons; A1, A2 and A3 are 1,4-cyclohexylene or 1,4-phenylene; Z1 and Z2 are single bonds, —(CH2)2—, —CH═CH—, —COO—, —OCO—, —CF2O—, —OCF2—, —CH2O— or —OCH2—; Y1 is —CF2H or —CF3; Y2 is fluorine; and a, b and d are 0, 1, 2 or 3, and c is 1 or 3.