Liquid Crystal Composition for Low-Temperature Display Stability
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Solution Overview
Problem
Current liquid crystal compositions have a narrow liquid crystal range, leading to poor display performance at low temperatures, with high melting points, high rotational viscosity, small dielectric and optical anisotropy, and short signal response times, making them unsuitable for continuous display below −20°C and causing ghosting issues.
Innovation Solution
A liquid crystal composition comprising compounds with specific structural formulas (I) and (II), which enhance miscibility and stability, lowering the melting point to −50°C, increasing dielectric and optical anisotropy, and reducing rotational viscosity, allowing for a wide nematic phase temperature range and improved display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid crystal compositions are used, then manufacturing simplicity is maintained, but the liquid crystal range is narrow and low-temperature display performance is poor
Solution Approach 1:
The patent employs a composite liquid crystal composition comprising multiple specific compounds (cyclic carbonate compounds, cyclic carboxylate compounds, and other liquid crystal compounds) in defined weight ratios. This composite approach broadens the liquid crystal range and improves low-temperature display performance by combining the complementary properties of different compounds, achieving reliable operation from −30°C to 100°C.
Solution Approach 2:
The patent optimizes the weight percentages of each compound component within specific ranges (cyclic carbonate compound: 5-20%, cyclic carboxylate compound: 5-20%, other liquid crystal compounds: 60-80%). By precisely controlling these compositional parameters, the invention achieves both improved low-temperature reliability and maintains manufacturing feasibility through defined formulation specifications.
2Speed
If liquid crystal composition with high melting point is used, then thermal stability is improved, but rotational viscosity increases and response time becomes slow
Solution Approach 1:
The patent carefully selects and balances the melting points of individual compounds in the composition. By combining compounds with different melting point characteristics in specific ratios, the overall composition achieves an optimal balance where the liquid crystal phase remains stable at operating temperatures while maintaining low rotational viscosity for fast response times.
Solution Approach 2:
The composite formulation combines cyclic carbonate compounds and cyclic carboxylate compounds with other liquid crystal compounds having complementary thermal and rheological properties. This composite approach enables the composition to exhibit low rotational viscosity and fast response characteristics while maintaining appropriate thermal stability through the synergistic effect of multiple components.
3Reliability
If liquid crystal composition with small dielectric and optical anisotropy is used, then manufacturing simplicity is maintained, but display performance and contrast ratio deteriorate
Solution Approach 1:
The patent formulates a composite liquid crystal composition where cyclic carbonate compounds, cyclic carboxylate compounds, and other liquid crystal compounds are combined in specific proportions. This composite structure achieves high dielectric anisotropy and optical anisotropy values that enable superior display performance and contrast ratio, while the defined formulation maintains manufacturing simplicity through standardized production processes.
4Duration of action of moving object
If liquid crystal composition is optimized for fast response, then signal response time is reduced, but ghosting occurs and long-term display stability is compromised
Solution Approach 1:
The patent optimizes the compositional parameters within specific weight ratio ranges to achieve a balance between fast response and display stability. The controlled formulation ensures that the liquid crystal composition maintains consistent rheological and electro-optical properties over time, preventing ghosting while achieving rapid response times through optimized molecular interactions in the composite system.
Solution Approach 2:
The composite liquid crystal composition combines multiple compounds with complementary properties that work synergistically to provide both fast response characteristics and long-term display stability. The specific combination of cyclic carbonate compounds, cyclic carboxylate compounds, and other liquid crystal compounds creates a stable system that resists degradation and ghosting effects while maintaining rapid response capabilities.
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 achieves a wide nematic phase temperature range, low rotational viscosity, high dielectric and optical anisotropy, and stability, enabling fast response and long-term display without ghosting, suitable for extreme temperature environments.
Implementation Method 1
the liquid crystal composition has a melting point (S—N)≤−50° C. from a crystalline state to a nematic phase
Implementation Method 2
a dielectric anisotropy Δε of the liquid crystal composition is 6.1±0.5
Implementation Method 3
an optical anisotropy Δn of the liquid crystal composition is 0.118±0.005
Data Source
AI summary
A liquid crystal composition and a display device are provided. The liquid crystal composition includes a compound having a structure represented by general formula (I) and a compound having a structure represented by general formula (II),and L1, L2, L3 and L4 are independently selected fromZ1 is selected from a single bond or —C≡C—; R1, R2 and R3 are independently selected from alkyl, alkenyl, alkynyl, haloalkyl or OR4; and R4 is selected from alkyl, alkenyl, alkynyl or haloalkyl.