Liquid Crystal Composition for IPS Display Yield
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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 problems, especially with the one-drop-fill method, which requires precise liquid crystal composition and voltage control across varying temperatures and device sizes.
Innovation Solution
A liquid crystal composition combining specific compounds represented by general formulae (i), (ii), and (iii) is developed, offering positive or negative dielectric anisotropy, low viscosity, and improved solubility, stability, and resistivity, suitable for IPS or FFS devices, to enhance production yield and display quality.
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 the manufacturing efficiency is improved, but display quality degrades 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 (cyclohexylidene and phenylidene groups) to alter the fluid's physical properties. This enables the liquid crystal to maintain stability during the one-drop-fill injection process while preventing drop mark formation, thus resolving the contradiction between manufacturing efficiency and display quality.
2Ease of manufacture
If the amount of liquid crystal dropped significantly deviates from the optimum value, then the production process becomes simpler, but display failures occur such as nonuniformity and contrast failures
Solution Approach 1:
The patent adjusts the compositional parameters of the liquid crystal mixture to achieve optimal viscosity and flow characteristics. This allows the liquid crystal to be reliably injected in the one-drop-fill method with consistent filling volume, preventing display failures while maintaining production simplicity.
3Volume of moving object
If small-size liquid crystal display devices are produced with small optimum liquid crystal injection amount, then the device size is reduced, but it becomes difficult to control deviation from the optimum value
Solution Approach 1:
The patent modifies the liquid crystal composition parameters to achieve precise control over viscosity and flow behavior. This enables accurate injection of small volumes required for miniaturized devices while minimizing deviation from the optimum injection amount, thus maintaining manufacturing precision despite reduced device size.
4Speed
If liquid crystal composition is optimized for high-speed response with low rotational viscosity, then the response speed is improved, but the stability against external factors may be compromised
Solution Approach 1:
The patent creates a composite liquid crystal mixture containing multiple compounds with specific molecular structures (cyclohexylidene and phenylidene groups). This composite formulation achieves low rotational viscosity for high-speed response while maintaining stability against external factors through the synergistic effects of the combined components.
5Adaptability or versatility
If liquid crystal composition has positive dielectric anisotropy for horizontal alignment display, then the display mode versatility is improved, but the viscosity control becomes more challenging
Solution Approach 1:
The patent adjusts the compositional parameters of the liquid crystal mixture, incorporating specific compounds with cyclohexylidene and phenylidene groups that provide positive dielectric anisotropy. The formulation is optimized to achieve the required viscosity characteristics while maintaining the positive dielectric anisotropy needed for horizontal alignment display modes.
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 exhibits a wide temperature range stability, low viscosity, and high resistivity, reducing display failures and enabling high-yield production of liquid crystal display devices with improved response speed and reliability.
Implementation Method 1
a liquid crystal composition having positive negative Δε... uses a liquid crystal composition having positive Δε... positive Δε with a large absolute value
Implementation Method 2
optimize dielectric anisotropy (Δε) and/or refractive index anisotropy (Δn)... the product of Δn and cell gap (d), Δn of the liquid crystal composition must be adjusted
Implementation Method 3
nematic phase-isotropic liquid phase transition temperature (Tni)... exhibit a liquid crystal phase in a temperature range as wide as possible around room temperature
Data Source
AI summary
An object of the present invention is to provide a composition that has positive Δε, 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 selected from compounds represented by general formula (iii). Moreover, a liquid crystal display device using the composition and an IPS or FFS device that uses the composition are provided.