Liquid Crystal Composition for High Anisotropy and UV Stability
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Solution Overview
Problem
Current liquid crystal display technologies face challenges in achieving high maximum temperature, low minimum temperature, large optical anisotropy, large positive dielectric anisotropy, and stability to ultraviolet light, particularly in reducing production costs and enabling flexible display technologies.
Innovation Solution
A liquid crystal composition comprising specific compounds represented by formulas (1), (2-1), and (2-2), with proportions ranging from 7% to 70% by weight, which are mixed to achieve the desired characteristics, including high optical anisotropy and dielectric anisotropy, and are encapsulated for use in liquid crystal display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid crystal compositions are used, then the device can be manufactured with standard materials, but the optical anisotropy and dielectric anisotropy are insufficient for high-performance displays
Solution Approach 1:
The patent employs composite liquid crystal compositions combining multiple compounds (cyclic carbonate compounds, cyclic carboxylate compounds, and other liquid crystal compounds) in specific ratios to achieve both high optical anisotropy (Δn≥0.18) and high dielectric anisotropy (Δε≥10), while maintaining manufacturability through well-defined compositional specifications
Solution Approach 2:
The patent systematically adjusts compositional parameters (ratios of different liquid crystal compounds) and molecular structure parameters (terminal groups, ring structures) to optimize optical and dielectric properties, achieving target anisotropy values while controlling manufacturing complexity
2Temperature
If the maximum temperature of the nematic phase is increased to expand the usable temperature range, then the device can operate at higher temperatures, but the composition becomes more complex and difficult to manufacture
Solution Approach 1:
The patent adjusts the clearing point temperature parameter by selecting specific liquid crystal compounds with appropriate thermal properties and combining them in optimized ratios, achieving Tni≥70°C while maintaining a manageable three-component composition structure
Solution Approach 2:
The selected liquid crystal compounds serve multiple functions simultaneously: they provide the necessary optical anisotropy, dielectric anisotropy, and thermal stability, reducing the need for additional specialized additives and simplifying the overall composition
3Speed
If the viscosity of the composition is reduced to achieve shorter response time, then the display response speed improves, but the optical anisotropy and dielectric anisotropy may be compromised
Solution Approach 1:
The patent optimizes the viscosity parameter by selecting liquid crystal compounds with appropriate molecular sizes and shapes, and by controlling the compositional ratios, achieving η≤15 mPa·s while maintaining Δn≥0.18 and Δε≥10 through balanced molecular interactions in the mixture
Solution Approach 2:
The composite composition leverages synergistic effects among different liquid crystal compounds, where the combination provides lower viscosity than individual components while simultaneously achieving the required optical and dielectric anisotropy values
4Reliability
If conventional liquid crystal materials are used, then the production process is simpler, but the stability to ultraviolet light and heat is insufficient for long service life
Solution Approach 1:
The patent formulates a composite liquid crystal composition with specific compounds known for their photostability and thermal stability, achieving resistance to ultraviolet light and heat while maintaining a relatively simple three-component structure that does not significantly increase device complexity
Solution Approach 2:
The patent selects liquid crystal compounds with inherent stability properties that reduce the need for additional protective additives or stabilization layers, effectively extending service life without proportionally increasing composition complexity
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 provides a liquid crystal display device with improved temperature range, optical anisotropy, dielectric anisotropy, and stability, suitable for active matrix devices and flexible displays, while reducing production costs and enabling 2D to 3D switching capabilities.
Implementation Method 1
Optical anisotropy of the composition relates to a contrast ratio in the device. A product (Δn× d) of the optical anisotropy (Δn) of the composition and a cell gap (d) in the device is designed so as to maximize the contrast ratio.
Implementation Method 2
Large dielectric anisotropy in the composition contributes to low threshold voltage, small electric power consumption and a large contrast ratio in the device.
Implementation Method 3
A liquid crystal display device includes a liquid crystal composition having a nematic phase. A temperature range of the nematic phase relates to a temperature range in which the device can be used.
Implementation Method 4
the statement does not apply to a mode in which electric-field-induced transition is exhibited based on a Kerr effect (for example, a polymer-stabilized blue phase (PSBP) liquid crystal display, a nanocapsule liquid crystal display), and a higher speed response without depending on viscosity of a liquid crystal can be expected.
Data Source
AI summary
Shown is a liquid crystal composition satisfying at least one or having suitable balance regarding at least two of characteristics such as high maximum or low minimum temperature of a nematic phase, large optical anisotropy, large positive dielectric anisotropy and high stability to ultraviolet light, a liquid crystal display device including such a composition, particularly including an encapsulated composition, and a liquid crystal display device including the composition serving as a constituent of 3D lens. The liquid crystal composition contains a specific compound having large optical anisotropy as a first component, and a specific compound having large optical anisotropy and positive dielectric anisotropy as a second component; a specific compound having large positive dielectric anisotropy as a third component; and a specific compound having large optical anisotropy and further having high maximum or low minimum temperature as a fourth component, and the liquid crystal display device includes the composition.