Liquid Crystal Composition for Drop Mark Reduction
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Solution Overview
Problem
Liquid crystal display elements face issues with drop marks and ghosting during production, which degrade display quality and yield, particularly in vertical alignment and in-plane-switching modes, due to impurities and additives in the liquid crystal composition.
Innovation Solution
A liquid crystal composition is developed using specific compounds at particular mixing ratios, including those represented by formulas (I), (II), (III), (IV), and (VI), to minimize drop marks and maintain high-speed responsiveness while reducing ghosting and maintaining essential properties like dielectric anisotropy and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If monomers and additives are added to the liquid crystal composition to create pretilt angle and increase response speed, then response speed is improved, but drop marks occur and display quality degrades
Solution Approach 1:
The invention extracts and removes harmful impurities and additives (such as monomers, antioxidants, and light absorbers) from the liquid crystal composition that cause drop marks during the ODF process, while maintaining the essential functional components needed for display performance
Solution Approach 2:
The invention changes the chemical composition parameters of the liquid crystal mixture by selecting specific compounds with appropriate purity levels and excluding certain additive classes, thereby eliminating drop mark formation while preserving response speed characteristics
2Reliability
If compounds with ester bonds are used to achieve certain liquid crystal properties, then liquid crystal performance is improved, but yield degradation occurs due to display defects
Solution Approach 1:
The invention converts the potential harm of ester bond compounds by carefully selecting specific ester-containing liquid crystal compounds that do not interfere with the ODF process, thereby maintaining their beneficial liquid crystal properties while avoiding yield degradation
Solution Approach 2:
The invention applies local quality control by permitting ester bond compounds in specific positions and concentrations within the liquid crystal composition, while restricting other harmful additives, thus achieving both performance and yield optimization
3Productivity
If liquid crystal composition is dropped onto substrate using ODF method for large size displays, then production efficiency is improved, but drop marks occur and display quality degrades
Solution Approach 1:
The invention extracts and eliminates the root cause of drop marks by removing impurities and problematic additives from the liquid crystal composition, enabling the ODF method to proceed without quality degradation
Solution Approach 2:
The invention accepts the temporary presence of certain components during the dropping process that can be easily removed or do not persist in the final product, focusing on eliminating the persistent harmful impurities that cause drop marks
Data Source
Figure 1~2
AI summary
The present invention relates to a liquid crystal composition used in a liquid crystal display element. An object of the present invention is to provide a liquid crystal composition suitable for use in a liquid crystal display element that suffers less from drop marks that occur during production without degrading ghosting properties of the display element and various properties of the liquid crystal display element, such as dielectric anisotropy, viscosity, nematic phase upper limit temperature, low-temperature nematic phase stability, and γ1, and with which a stable amount of a liquid crystal material can be discharged in an ODF process. A liquid crystal display element that uses the liquid crystal composition is also provided. The present invention relates to a liquid crystal composition having negative dielectric anisotropy and containing a compound represented by formula (I), one or more compounds represented by general formula (II-1), and one or more compounds represented by general formula (II-2). The present invention also relates to a liquid crystal display element that uses the liquid crystal composition.