Liquid Crystal Composition for High Transmittance Displays
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Solution Overview
Problem
Current liquid crystal display technologies face challenges with low transmittance, high energy consumption, and slow response times, particularly in TFT-LCDs, due to limitations in liquid crystal material properties such as viscosity, dielectric constants, and refractive index.
Innovation Solution
A liquid crystal composition comprising specific compounds represented by formulas I, II, III, and IV, which enhance dielectric constants, reduce rotary viscosity, and increase clearing point, thereby improving transmittance and response speed, while maintaining stability to light and heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional liquid crystal materials are used in TFT-LCDs, then the display device can operate, but the transmittance is low (only 3-10%) and energy consumption is high
Solution Approach 1:
The patent modifies the molecular structure of liquid crystal compounds by introducing specific substituents (fluoro, cyano, alkoxy groups) and adjusting molecular weight and shape to optimize optical and electrical parameters. This changes the dielectric constant, rotary viscosity, and refractive index to improve transmittance and reduce energy consumption
Solution Approach 2:
The patent creates a composite liquid crystal composition by blending multiple different liquid crystal compounds together. This composite approach allows the mixture to achieve superior transmittance and response characteristics that individual compounds cannot attain alone, while maintaining stability and compatibility
2Speed
If the rotary viscosity γ1 is reduced to achieve faster response speed, then the response time decreases, but the liquid crystal material becomes harder to control and stability decreases
Solution Approach 1:
The patent carefully adjusts molecular parameters such as chain length, substituent types, and molecular weight to achieve the optimal balance between rotary viscosity and stability. By introducing specific rigid and flexible groups in controlled proportions, the material achieves fast response while maintaining structural integrity and stability
Solution Approach 2:
The patent introduces different functional groups at specific positions of the liquid crystal molecule (e.g., fluoro groups at terminal positions, cyano groups at specific locations) to locally modify properties. This allows different parts of the molecule to contribute differently to viscosity and stability, achieving overall optimization
3Loss of time
If the drive voltage is increased to reduce response time (ton), then the rise time improves, but the energy consumption increases and the device complexity increases
Solution Approach 1:
The patent modifies the dielectric anisotropy (Δε) and dielectric constant (ε) of the liquid crystal material through molecular structure optimization. By increasing Δε and adjusting ε, the material becomes more responsive to electric fields, allowing faster response at lower drive voltages
Solution Approach 2:
The patent replaces the need for high mechanical/electrical drive power by optimizing the material's inherent electrical properties. The enhanced dielectric characteristics allow the liquid crystal to respond more efficiently to applied voltages, substituting material property optimization for increased drive power
4Productivity
If the cell thickness is reduced to improve response time and transmittance, then the response speed and light transmission improve, but the manufacturing precision requirements increase and the yield decreases
Solution Approach 1:
The patent optimizes the liquid crystal material's viscosity and elastic constant parameters to compensate for reduced cell thickness. By adjusting these material parameters, the system maintains stable performance even with thinner cells, reducing the stringency of manufacturing tolerance requirements
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 composition significantly increases transmittance and reduces energy consumption by enhancing dielectric constants and response speed, leading to higher brightness and longer device service life.
Implementation Method 1
both larger dielectric constants in the parallel direction and vertical direction to the long-axis of the liquid crystal molecule and smaller dielectric anisotropies (Δε)
Implementation Method 2
an optical anisotropy (Δn) matching with TFT-LCD, which eliminates a rainbow effect and gives better contrast and viewing angle properties
Data Source
AI summary
Disclosed are a liquid crystal composition, a liquid crystal display element, and a liquid crystal display, said liquid crystal composition comprising one or more compounds represented by formula I, one or more compounds represented by formula II, one or more compounds represented by formula III and one or more compounds represented by formula IV,The liquid crystal composition of the present invention has a good stability to light and heat and a lower viscosity, and can attain a wider refractive index and a high clearing point (a wide service temperature range), and in particular, the liquid crystal composition has a high light transmittance, thus allowing a display device to have a high brightness or an energy saving effect.