Liquid Crystal Aligning Agent Composition for High Transmittance
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Solution Overview
Problem
Conventional liquid crystal display technologies face challenges in achieving low discoloration during long-term storage, high light transmittance, and improved electrical and alignment properties, particularly in high temperature environments, due to limitations in existing liquid crystal aligning agents and methods such as the rubbing and photo-alignment methods.
Innovation Solution
A liquid crystal aligning agent composition comprising a polymer with a polyamic acid, polyamic acid ester, or polyimide repeating unit, combined with a terminal modifier compound, which reacts with primary amino groups to enhance light transmittance and electrical reliability, and a method involving coating, drying, light irradiation or rubbing, and heat-treating the composition to form a liquid crystal alignment film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rubbing method is used to align liquid crystals, then alignment properties are improved, but fine dust and electrostatic discharge occur during manufacturing
Solution Approach 1:
The patent replaces the mechanical rubbing method with a photo-alignment method using light irradiation. The polymer film is coated on the substrate and then irradiated with polarized light to induce anisotropy and align liquid crystals, eliminating the need for mechanical contact and thus preventing dust generation and electrostatic discharge while maintaining alignment functionality
2Reliability
If polyimide is used for photo-alignment, then alignment performance is improved, but solubility is poor making direct solution coating difficult
Solution Approach 1:
The patent uses polyamic acid or polyamic acid ester as a precursor material before the final polyimide formation. These precursors have excellent solubility in common solvents, allowing easy solution coating. After coating, a heat treatment process converts the precursor to polyimide, which then provides the desired alignment performance through light irradiation
3Ease of manufacture
If conventional aligning agents are used, then manufacturing is simplified, but discoloration occurs during long-term storage reducing light transmittance
Solution Approach 1:
The patent develops a composite aligning agent composition containing polyimide or its precursor combined with specific additives including hindered amine light stabilizers (HALS) and ultraviolet absorbers. This composite formulation maintains manufacturing simplicity while providing excellent long-term storage stability, preventing discoloration and maintaining high light transmittance through the synergistic effect of the stabilizer components
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 solution results in a liquid crystal alignment film with high light transmittance and improved electrical and alignment properties, maintaining stability and performance even during long-term storage and high temperature conditions.
Implementation Method 1
a terminal modifier compound which reacts with primary amino groups to enhance light transmittance and electrical reliability
Implementation Method 2
a photo-alignment method for inducing anisotropy in a polymer film by light irradiation rather than by rubbing, and aligning liquid crystals using anisotropy
Implementation Method 3
a heat treatment process is performed at a temperature of 200° C. to 230° C. to form a polyimide
Data Source
AI summary
The present invention relates to a liquid crystal aligning agent composition including a terminal modifier of a specific chemical structure together with a polyimide or a precursor polymer thereof.