Self-Assembled Monolayer Alignment Layer for Liquid Crystal Displays
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Solution Overview
Problem
In vertical electric field type liquid crystal displays, the use of reactive mesogens for aligning liquid crystal molecules can result in afterimage defects due to uncured mesogen remnants after the curing process, and there is a need for improved alignment layer uniformity to prevent light leakage and afterimage formation.
Innovation Solution
A display device with alignment layers that include an initial alignment layer and a self-assembled monolayer with polymerizable or electrically polarized functional groups, which form a network structure to effectively pretilt liquid crystal molecules, eliminating the need for a phase separation process and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactive mesogen is used for aligning liquid crystal molecules, then alignment uniformity is improved, but uncured mesogen remnants cause afterimage defects
Solution Approach 1:
The patent extracts and removes the harmful uncured reactive mesogen components from the alignment layer through a two-stage curing process. The first curing stage at 100-150°C for 1-24 hours partially cures the mesogen, and the second curing stage at 200-300°C for 1-10 hours completely cures remaining mesogen, eliminating afterimage defects while maintaining alignment uniformity.
Solution Approach 2:
The patent applies preliminary alignment treatment before final curing by first aligning liquid crystal molecules using the reactive mesogen, then performing partial curing, and finally completing the curing process. This preliminary action ensures proper molecular orientation is established before the final cure that removes uncured remnants.
2Manufacturing precision
If alignment layer uniformity is improved to prevent light leakage, then display quality is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent combines the alignment function and the curing process into a single integrated manufacturing workflow. The alignment layer is formed with reactive mesogen that serves both alignment and self-curing functions, merging what could be separate processes into one unified approach that improves uniformity without proportionally increasing complexity.
Solution Approach 2:
The patent utilizes parameter changes in the curing process by adjusting temperature and time conditions across two stages. The first stage uses 100-150°C for 1-24 hours, then the second stage uses 200-300°C for 1-10 hours, optimizing both alignment uniformity and complete curing while managing manufacturing complexity through controlled parameter progression.
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 provides improved uniformity and prevents afterimage and light leakage issues by effectively pretilting liquid crystal molecules, enhancing the display's performance and reliability.
Implementation Method 1
polymerizing the first functional group to form a network in the self-assembled monolayer
Implementation Method 2
a self-assembled monolayer having a third functional group polarized by an electric field
Data Source
AI summary
A display device includes a first substrate, a first alignment layer disposed on the first substrate, a second substrate, a second alignment layer disposed on the second substrate, and a liquid crystal layer disposed between the first and second alignment layers and having liquid crystal molecules. At least one of the first and second alignment layers includes an initial alignment layer and a pretilting layer including a self-assembled monolayer disposed on the initial alignment layer.