Liquid Crystal Photoalignment Agent Copolymer for Uniform Alignment
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Solution Overview
Problem
Existing liquid crystal display technologies face challenges in achieving uniform liquid crystal alignment due to issues like fine dust and static electricity in rubbing methods, leading to suboptimal image quality and afterimages.
Innovation Solution
A liquid crystal photoalignment agent is developed, comprising a copolymer of cyclobutanedianhydride, diamine, and a compound with a flexible structure, which is applied and irradiated with polarized light to form alignment layers, enhancing anisotropy and decomposition efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rubbing method is used to align liquid crystals, then liquid crystal alignment can be achieved, but fine dust and static electricity occur causing manufacturing problems
Solution Approach 1:
The patent replaces the mechanical rubbing method with a photoalignment method using light irradiation. The polymer layer is treated with polarized light to create anisotropic alignment without physical contact, thereby eliminating dust generation and static electricity while achieving uniform liquid crystal alignment.
Solution Approach 2:
The patent utilizes photoinduced phase transition in the polymer layer. Upon irradiation with polarized light, the polymer undergoes a phase change that creates anisotropic refractive index, enabling liquid crystal alignment without mechanical rubbing. This phase transition mechanism eliminates the harmful effects of the rubbing method.
2Object-generated harmful factors
If a photoalignment method is used to eliminate dust and static electricity, then manufacturing quality improves, but alignment uniformity and decomposition efficiency need enhancement
Solution Approach 1:
The patent employs a composite polymer layer comprising multiple components: a first polymer providing basic alignment, a second polymer enhancing anisotropy, and a third polymer improving decomposition efficiency. This composite structure achieves superior alignment uniformity and eliminates the trade-off between eliminating harmful factors and maintaining precision.
Solution Approach 2:
The patent optimizes multiple parameters including the molecular structure of polymer components, their weight ratios, irradiation light intensity and wavelength, and heat treatment temperature. By systematically adjusting these parameters, the patent achieves both elimination of harmful factors and enhancement of alignment uniformity.
3Ease of manufacture
If conventional photoalignment agents are used, then manufacturing is simplified, but afterimage problems persist due to insufficient decomposition efficiency
Solution Approach 1:
The patent introduces a composite photoalignment agent system with three different polymer components, each contributing specific functions. The third polymer component specifically enhances decomposition efficiency under light irradiation, enabling complete photoalignment without afterimages while maintaining manufacturing simplicity.
Solution Approach 2:
The patent employs a two-stage treatment process: first, irradiation with polarized light to create initial alignment; second, heat treatment to complete the alignment and eliminate afterimages. This periodic action ensures complete decomposition and alignment without compromising manufacturing simplicity.
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 improves the alignment uniformity and reduces afterimages by increasing the anisotropy and decomposition efficiency of the liquid crystal photoalignment agent, resulting in better image quality and reduced manufacturing defects.
Implementation Method 1
a photoalignment method where anisotropy is induced to the polymer layer by irradiation of light and the liquid crystals are arranged by using anisotropy
Implementation Method 2
irradiation of light and the liquid crystals are arranged by using anisotropy
Implementation Method 3
a liquid crystal photoalignment agent having excellent anisotropy and decomposition efficiency
Data Source
AI summary
A liquid crystal display includes a first substrate, a thin film transistor positioned on the first substrate, a first electrode connected to the thin film transistor, a second substrate facing the first substrate, a first alignment layer positioned on the first electrode and a second alignment layer positioned on the second substrate, and a liquid crystal layer positioned between the first substrate and the second substrate and including a liquid crystal molecule. At least one of the first alignment layer and the second alignment layer includes a copolymer of cyclobutanedianhydride (CBDA), a diamine, and a compound represented by Chemical Formula 2.In which X of Chemical Formula 2 represents —(CH2)m-O—(CH2)n—, and a sum of m and n is an odd number.