Liquid Crystal Composition for IPS Display Yield and Stability
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Solution Overview
Problem
Liquid crystal display devices face challenges in maintaining high-quality display and stability due to issues like image-sticking, drop marks, and viscosity changes during the one-drop-fill method, requiring a composition that exhibits a wide temperature range, low viscosity, and high resistivity while ensuring high-yield production and resistance to external factors.
Innovation Solution
A liquid crystal composition combining specific compounds represented by general formulae (i), (ii), and (iii) is developed, which includes alkyl and alkenyl groups, providing positive or negative dielectric anisotropy, low viscosity, and improved solubility, stability, and resistivity, suitable for IPS or FFS devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the one-drop-fill method is used to inject liquid crystal composition into large substrate, then productivity is improved, but display quality deteriorates due to drop marks
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid crystal mixture, specifically incorporating compounds with particular molecular structures (cyclic structures with specific substituents) to alter physical properties like viscosity and surface tension, enabling stable dropping without drop marks while maintaining high productivity
Solution Approach 2:
The patent uses a composite liquid crystal composition containing multiple compounds including cyclic compounds with specific substituents, combined in optimized ratios to achieve both low viscosity for easy dropping and appropriate surface tension to prevent drop marks, resolving the contradiction between productivity and display quality
2Ease of manufacture
If the amount of liquid crystal dropped deviates from optimum value, then productivity is improved by simplifying control, but display quality deteriorates due to nonuniformity and contrast failures
Solution Approach 1:
The patent adjusts the viscosity parameter of the liquid crystal composition through selective compound selection, creating a viscosity range that provides natural flow control during dropping, reducing sensitivity to injection amount variations and eliminating the need for precise control while maintaining display uniformity
3Adaptability or versatility
If liquid crystal composition has small injection amount for small-size devices, then adaptability is improved, but manufacturing precision deteriorates due to difficulty in controlling deviation from optimum value
Solution Approach 1:
The patent modifies the surface tension and viscosity parameters of the liquid crystal composition, creating a material that maintains stable droplet formation and flow characteristics across different injection volumes, enabling precise filling even in small-size devices where injection amount deviation is difficult to control
4Speed
If liquid crystal composition requires high-speed response for television applications, then response speed is improved, but viscosity must be reduced which may affect stability
Solution Approach 1:
The patent creates a composite liquid crystal composition with multiple compounds in specific ratios, where the combination achieves low rotational viscosity for fast response while the overall composition maintains appropriate stability characteristics, resolving the trade-off between response speed and composition stability
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 high-speed response, stability against heat and light, and reduced display failures, enabling high-yield production of liquid crystal display devices with improved display quality and resistance to external factors.
Implementation Method 1
liquid crystal composition having negative Δε
Implementation Method 2
optimize dielectric anisotropy (Δε) and/or refractive index anisotropy (Δn)
Data Source
AI summary
An object of the present invention is to provide a composition that has positive .DELTA..epsilon., exhibits a liquid crystal phase over a wide temperature range, has low viscosity, excellent solubility at low temperatures, and high resistivity and voltage holding ratio, and is stable against heat and light. By using this composition, IPS or TN liquid crystal display devices and the like that have excellent display quality and suppress display failures such as image-sticking and drop marks are provided in high yield. Provided is a composition that contains at least one selected from the group consisting of compounds represented by general formulae (i) and (ii) and at least one compound represented by general formula (iii). Also provided is a liquid crystal display device that uses the composition and an IPS or FFS device that uses the composition.