Liquid Crystal Display Alignment Layer Polymerization Inhibition
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Solution Overview
Problem
Liquid crystal displays face issues with afterimages and reliability, particularly in achieving wide viewing angles and rapid response times, which are not adequately addressed by existing technologies.
Innovation Solution
Incorporating a reactive mesogen into the alignment layer or liquid crystal layer with side chains containing a polymerization inhibiting agent group, along with bumps formed by polymerization of alignment polymers, to control pre-tilt angles and suppress polymerization, thereby enhancing mechanical properties and reducing afterimage problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a reactive mesogen is added to the alignment layer to create pre-tilt angles for wide viewing angle and fast response, then the viewing angle and response speed are improved, but polymerization occurs during baking which causes afterimage problems and reduces reliability
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a polymerization inhibiting agent into the alignment layer before baking. This agent prevents polymerization of the reactive mesogen during the thermal processing stage, counteracting the harmful effect before it can occur. The inhibiting agent is specifically designed to suppress polymerization reactions that would otherwise be triggered by heat during alignment layer formation, thereby preventing afterimage problems while maintaining the beneficial pre-tilt angle effect.
Solution Approach 2:
The polymerization inhibiting agent acts as an intermediary substance between the reactive mesogen and the thermal energy during baking. It mediates the interaction by selectively binding to or stabilizing the reactive mesogen, preventing unwanted polymerization reactions while allowing the necessary alignment and pre-tilt angle formation to occur. This intermediary protects the liquid crystal system from degradation during manufacturing.
2Ease of manufacture
If the alignment layer is baked to initiate imidization and discharge reactive mesogen, then the alignment layer formation is completed, but polymerization occurs causing afterimage problems
Solution Approach 1:
The patent converts the harmful polymerization reaction into a beneficial controlled process by using the polymerization inhibiting agent. The agent allows the baking process to proceed for proper alignment layer formation and reactive mesogen discharge, but controls polymerization to occur only in a controlled manner that forms desirable bump structures rather than causing harmful afterimages. The harmful thermal energy that causes polymerization is thus converted into a controlled structural formation process.
Solution Approach 2:
The patent applies parameter changes by modifying the chemical composition of the alignment layer through the addition of the polymerization inhibiting agent. This changes the thermal and chemical parameters of the system during baking, allowing the process to proceed at necessary temperatures for imidization and reactive mesogen discharge while suppressing unwanted polymerization. The parameter change enables the baking process to achieve alignment layer formation without generating afterimage defects.
3Shape
If reactive mesogen is discharged into the liquid crystal layer during baking, then pre-tilt angle is formed, but polymerization reduces mechanical properties
Solution Approach 1:
The patent applies preliminary action by pre-incorporating the polymerization inhibiting agent into the alignment layer structure before the baking and reactive mesogen discharge processes. This preliminary preparation ensures that when the reactive mesogen is discharged and polymerization is initiated, the inhibiting agent is already in position to control the reaction. This preliminary protective measure ensures that pre-tilt angle formation occurs while mechanical properties are preserved from the outset.
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 afterimage issues and reliability by increasing the degree of polymerization and mechanical properties, resulting in better performance for wide viewing angles and response speed.
Implementation Method 1
the side chains comprise a polymerization inhibiting agent group. Especially the alignment layer may consist of or comprise a polymer with a corresponding main chain and side chains... the polymerization inhibiting agent group suppresses polymerization by heat
Implementation Method 2
light-irradiating while an electric field is applied thereto, wherein the side chain includes a polymerization inhibiting agent group, and the alignment assistant agent discharged to the liquid crystal layer is polymerized when the light is irradiated such that bumps are formed
Data Source
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AI summary
A liquid crystal display including a first substrate (110); a second substrate (210) facing the first substrate (110); an alignment layer (11, 21) disposed on at least one of the first substrate and the second substrate; a liquid crystal layer (3) disposed between the first substrate and the second substrate and including a reactive mesogen; and bumps (15, 25) disposed adjacent to a surface of the alignment layer, wherein the alignment layer comprises a main chain and a plurality of side chains connected to the main chain, and the side chains comprise a polymerization inhibiting agent group.