Liquid Crystal Alignment Agent Composition with Silane Crosslinker
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Solution Overview
Problem
Conventional liquid crystal alignment methods, such as the rubbing method and photo-alignment method using polyimide, face challenges with storage stability, uniformity, and electrical characteristics, particularly in high-performance and low-power liquid crystal display devices, where high film strength and voltage holding ratio are essential.
Innovation Solution
A liquid crystal alignment agent composition is developed, incorporating a polymer and a crosslinker compound with a silicon-containing thermally removable protecting group, which limits the change in particle number during storage, ensuring stability and uniformity, and enhancing film strength and electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide is used for photo-alignment method, then liquid crystal alignment properties are improved, but storage stability and uniformity deteriorate due to particle formation during storage
Solution Approach 1:
A silane-based crosslinking agent is introduced as an intermediary substance that reacts with polyimide to form a crosslinked network structure. This crosslinked structure acts as a stabilizing framework that prevents particle formation and maintains composition uniformity during storage, while preserving the liquid crystal alignment properties provided by polyimide
Solution Approach 2:
The invention creates a composite material system combining polyimide with silane-based crosslinking agents. This composite structure leverages the alignment properties of polyimide while the crosslinked silane network provides enhanced storage stability and prevents particle formation, resolving the contradiction between alignment performance and storage stability
2Strength
If crosslinking agents are added to improve film strength, then film strength is improved, but storage stability and uniformity deteriorate due to compound instability
Solution Approach 1:
The invention changes the chemical parameters of the crosslinking agent by selecting silane-based compounds with specific functional groups that provide both crosslinking capability and storage stability. The silane structure with appropriate hydrolyzable groups allows controlled crosslinking while maintaining solution stability during storage, resolving the contradiction between film strength and storage stability
3Strength
If conventional crosslinker compounds are used, then film strength is improved, but electrical characteristics deteriorate at high temperature and low frequency
Solution Approach 1:
The silane-based crosslinking agent provides localized crosslinking regions that strengthen the film structure without creating large-scale inhomogeneities. This localized crosslinking maintains the overall electrical properties of the polyimide matrix even at high temperatures and low frequencies, while still providing the necessary film strength enhancement
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 improved storage stability, reliability, and electrical characteristics, enabling the production of liquid crystal alignment films with high film strength and excellent alignment properties, suitable for high-performance liquid crystal display devices.
Implementation Method 1
a liquid crystal alignment agent composition including a polymer for liquid crystal alignment agent and a crosslinker compound in which a terminal crosslinking functional group is capped with a silicon-containing thermally removable protecting group
Implementation Method 2
a crosslinker compound in which a terminal crosslinking functional group is capped with a silicon-containing thermally removable protecting group
Data Source
AI summary
The present disclosure relates to a liquid crystal alignment agent composition including: a polymer for liquid crystal alignment agent and a crosslinker compound in which a terminal crosslinking functional group is capped with a silicon-containing thermally removable protecting group, wherein a change in the number of particles during storage is lower than a certain level, a method for preparing a liquid crystal alignment film using the liquid crystal alignment agent composition, and a liquid crystal alignment film and a liquid crystal display device using the liquid crystal alignment agent film.