Reactive Mesogen Alignment Composition for LCD Panels
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Solution Overview
Problem
Existing alignment compositions for liquid crystal display panels, which include reactive mesogens as side chains of alignment polymers, often result in reduced mechanical strength and increased afterimage formation due to decreased cross-linking, affecting the display's transmissivity and response speed.
Innovation Solution
An alignment composition comprising an alignment polymer with a polyimide backbone and a vertical alignment side chain, combined with a reactive mesogen that is separated from the polymer, and a photo-reactive side chain with an epoxy group to increase cross-linking and mechanical strength, thereby improving afterimage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If reactive mesogen is included as a side chain of alignment polymer, then transmissivity and response speed are improved, but degree of cross-linking is reduced and mechanical strength is reduced
Solution Approach 1:
The invention separates the reactive mesogen from the alignment polymer structure. Instead of being incorporated as a side chain, the reactive mesogen is applied as a separate layer or mixed composition that contacts the alignment layer, allowing independent optimization of both alignment performance and cross-linking density.
Solution Approach 2:
The reactive mesogen is extracted from the polymer chain structure and applied separately. This allows the alignment polymer to maintain its structural integrity and cross-linking while the reactive mesogen provides the desired optical properties without compromising mechanical strength.
2Illumination intensity
If reactive mesogen is included as a side chain of alignment polymer, then transmissivity is improved, but degree of cross-linking is reduced
Solution Approach 1:
The invention divides the alignment system into separate functional components: the alignment polymer layer and the reactive mesogen layer. This segmentation allows each component to perform its specific function optimally without interfering with the cross-linking process of the polymer.
Solution Approach 2:
The reactive mesogen is extracted from the polymer structure and applied separately, enabling the polymer to achieve full cross-linking while the reactive mesogen provides enhanced transmissivity through its molecular structure and orientation.
3Speed
If reactive mesogen is included as a side chain of alignment polymer, then response speed is improved, but afterimage characteristics deteriorate
Solution Approach 1:
By separating the reactive mesogen from the alignment polymer, the invention allows the polymer matrix to maintain stable cross-linked structures that prevent afterimage formation, while the reactive mesogen layer provides fast response characteristics through its own molecular properties.
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 alignment composition enhances the mechanical strength of the reactive mesogen layer and reduces afterimage formation, leading to improved display quality with uniform brightness and high contrast ratio.
Implementation Method 1
a photo-reactive side chain with an epoxy group to increase cross-linking and mechanical strength
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
An alignment composition an alignment composition includes an alignment polymer and a reactive mesogen. The alignment polymer includes a polyimide backbone and a vertical alignment side chain combined with the polyimide backbone. The reactive mesogen may be represented by the following Chemical Formula 1. <Chemical Formula 1> MS-M1-M2-M3-M4 In Chemical Formula 1, M1 represents a divalent organic group including an aromatic ring group. M2 represents M3 represents a single bond, -O-, -O-(CH2)a-O-, or -(CH2)a-O-, wherein "a" represents an integer of 1 to 20. M4 represents an alkenyl group having a carbon number of 2 to 20 and including an unsaturated carbon bond as an end group, an alkynyl group having a carbon number of 2 to 20 and including an unsaturated carbon bond as an end group, an alkenylcarbonyl group having a carbon number of 3 to 20 and including an unsaturated carbon bond as an end group, an alkenylcarbonyloxy group having a carbon number of 3 to 20 and including an unsaturated carbon bond as an end group, a an oxotetrahydrofuryl group having -(C=CH2)- substituted for at least one -CH2-, or an epoxy group. M5 represents -M2-M3-M4 or -M3-M4.