Photo-Alignment Composition Merging Overcoating and Alignment Layers
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Solution Overview
Problem
Conventional liquid crystal alignment layers exhibit low transparency, poor solubility in common solvents, and inadequate heat and solvent resistance, leading to alignment failures and increased production costs in the manufacturing of liquid crystal displays.
Innovation Solution
A composition for forming thermoset films with photo-alignment properties, comprising a compound with a photo-aligning group and a hydroxy group, a polymer with hydroxy or carboxy groups, and a crosslinker, which can be dissolved in glycol-based or ketone solvents, enabling high transparency, solvent resistance, and heat resistance, and facilitating the formation of both liquid crystal alignment and overcoating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional acrylic resin is used for the overcoating layer, then high transparency is achieved, but satisfactory liquid crystal alignment properties cannot be exhibited even after rubbing process or polarized UV irradiation
Solution Approach 1:
The patent combines the overcoating layer and liquid crystal alignment layer into a single integrated layer. The composition contains acrylic resin (for transparency and overcoating function) together with polyimide or polyamic acid (for alignment properties), allowing both functions to be achieved simultaneously in one layer rather than requiring separate layers.
Solution Approach 2:
The invention uses a composite material system comprising acrylic resin combined with polyimide or polyamic acid. This composite provides both the optical properties of acrylic resin (transparency, solvent resistance) and the alignment properties of polyimide/polyamic acid, resolving the contradiction between transparency and alignment capability.
2Reliability
If a liquid crystal alignment layer is formed separately on top of the color filter overcoating, then satisfactory alignment properties are achieved, but production costs increase and the number of processes increases
Solution Approach 1:
The patent merges the overcoating layer and liquid crystal alignment layer into a single integrated layer. By incorporating both acrylic resin (for overcoating) and polyimide/polyamic acid (for alignment) in one composition, the need for separate formation processes is eliminated, reducing production steps and costs while maintaining alignment performance.
Solution Approach 2:
The single layer composition serves multiple functions simultaneously: it acts as both the protective overcoating layer (providing solvent resistance and durability) and the liquid crystal alignment layer (providing alignment properties through rubbing or UV irradiation). This multi-functionality eliminates the need for separate layers and processes.
3Reliability
If polyimide or polyamic acid is used for the liquid crystal alignment layer, then satisfactory alignment properties are achieved through rubbing process, but the material has low solubility in common solvents such as glycol-based solvents, esters, and ketones
Solution Approach 1:
The invention creates a composite material where polyimide or polyamic acid (providing alignment properties) is combined with acrylic resin and dissolved in common solvents like glycol-based solvents, esters, or ketones. The acrylic resin component acts as a solubilizing agent, enabling the polyimide/polyamic acid to be processed in conventional solvents while retaining its alignment capabilities.
Solution Approach 2:
The acrylic resin serves as an intermediary substance that enables solubility. It acts as a carrier or medium that allows the polyimide/polyamic acid to be dissolved in common solvents, facilitating ease of manufacture while preserving the alignment properties of the polyimide/polyamic acid component.
4Reliability
If the overcoating layer and liquid crystal alignment layer are formed as separate layers, then each layer can be optimized for its specific function, but the total number of production processes increases and costs increase
Solution Approach 1:
The patent combines two separate layers (overcoating and alignment layer) into a single integrated layer. The composition contains both acrylic resin (for overcoating function) and polyimide/polyamic acid (for alignment function), allowing both functions to be optimized within one layer rather than requiring two separate layers and their associated formation processes.
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 high solvent resistance, heat resistance, and efficient liquid crystal alignment with reduced production costs by forming a single layer that functions as both a liquid crystal alignment layer and an overcoating layer, enhancing the productivity and cost-effectiveness of liquid crystal display manufacturing.
Implementation Method 1
irradiating a compound having in a side chain thereof, a photodimerized moiety such as a cinnamoyl group and a calcone group with polarized UV, satisfactory liquid crystal alignment properties can be exhibited
Implementation Method 2
there is taken a technique for enhancing heat resistance and solvent resistance of the acrylic resin by thermo-curing or photo-curing the acrylic resin
Implementation Method 3
there is taken a technique for enhancing heat resistance and solvent resistance of the acrylic resin by thermo-curing or photo-curing the acrylic resin
Data Source
Figure 1(a)~1(b)
AI summary
There is provided a material that after the formation of a cured film, exhibits high solvent resistance, liquid crystal-alignment properties, heat resistance, and high transparency. A composition for forming thermoset film having photo-alignment properties and containing a component (A) that is a compound having a photo-aligning group and a hydroxy group, a component (B) that is a polymer having any one of or both of a hydroxy group and a carboxy group, and a component (C) that is a crosslinker.