Photoalignment Agent Copolymer for LCD Afterimage Reduction
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Solution Overview
Problem
Conventional liquid crystal display manufacturing methods, such as the rubbing method, often generate minute particles and electrostatic discharge, leading to alignment issues and afterimages, which affect display quality. The photoalignment method aims to improve alignment uniformity but faces challenges in enhancing afterimage problems.
Innovation Solution
A photoalignment agent is developed, comprising a copolymer of cyclobutanedianhydride (CBDA) or its derivative and a realignment property diamine with two or more aromatic rings connected by an ester group, which is polymerized and irradiated with polarized light to form alignment layers, improving afterimage and alignment uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubbing method is used to align liquid crystals, then alignment can be achieved, but minute particles and electrostatic discharge are generated causing afterimages and alignment issues
Solution Approach 1:
The patent replaces the mechanical rubbing method with a photoalignment method using light irradiation. The alignment layer contains photoreactive groups that undergo photoinduced isomerization or photochemical reactions when exposed to polarized light, creating anisotropic alignment without mechanical contact. This eliminates particle generation and electrostatic discharge while achieving uniform liquid crystal alignment.
Solution Approach 2:
The patent modifies the chemical structure of the alignment layer by incorporating specific photoreactive groups (cyclobutanedianhydride derivatives and diamines with aromatic rings connected by ester groups). These structural parameters enable photoinduced alignment properties, allowing the material to respond to light irradiation and achieve controlled anisotropy for improved alignment quality without mechanical rubbing.
2Object-generated harmful factors
If conventional photoalignment method is used, then afterimage problems are reduced, but alignment uniformity needs further improvement
Solution Approach 1:
The patent creates a composite alignment layer by copolymerizing cyclobutanedianhydride derivatives with specific diamines containing aromatic rings connected by ester groups. This composite structure combines the photoinduced alignment properties of CBDA with the molecular characteristics of the diamine, achieving both reduced afterimages and improved alignment uniformity through synergistic effects of the combined molecular structures.
Solution Approach 2:
The patent introduces specific local molecular structures (aromatic rings connected by ester groups in the diamine component) within the alignment layer that provide enhanced photoinduced anisotropy. These localized structural features with specific optical and chemical properties contribute to improved alignment uniformity while maintaining the overall photoalignment functionality to reduce afterimages.
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 proposed solution effectively reduces afterimages and enhances alignment uniformity in liquid crystal displays, improving display quality by using a copolymer of CBDA and realignment property diamine, which is polymerized and aligned with polarized light to form a photoalignment layer.
Implementation Method 1
a photoalignment method where anisotropy is provided to the polymer layer by light irradiation to align the liquid crystals
Implementation Method 2
the copolymer includes at least one repeating unit represented by Formula D, Formula E, and Formula F... A realignment product of the copolymer includes at least one compound represented by Formula G and Formula H
Data Source
AI summary
A photoalignment agent is provided. The photoalignment agent includes a copolymer of at least one of a cyclobutanedianhydride (CBDA) and a cyclobutanedianhydride (CBDA) derivative, and a realignment property diamine, wherein two or more aromatic rings in the realignment property diamine are connected by an ester group.