Polymer Stabilized LCD Alignment via Dual Monomer UV Polymerization
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Solution Overview
Problem
Current methods for fabricating polymer stabilized alignment (PSA) LCD panels are complex and result in slow response and decreased contrast ratio due to the use of polyimide (PI) alignment films, and PI-less technologies that vertically align liquid crystals only, leading to light leakage and reduced contrast.
Innovation Solution
A method involving a liquid crystal layer with monomers of single and multiple functional groups, where the monomer with single functional group forms alignment films and the monomer with multiple functional groups forms polymers to pre-tilt liquid crystals, using different UV light wavelengths for polymerization, allowing for vertical alignment and pre-tilting without increasing process complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide (PI) alignment films are used to fabricate PSA-LCD panels, then the liquid crystal molecules can be aligned, but the fabrication process complexity increases due to pre-cleaning, PI coating, pre-baking and post-baking steps
Solution Approach 1:
The patent extracts and removes the polyimide alignment film layer from the conventional PSA-LCD structure, replacing it with alignment protrusions formed directly on the substrate. This eliminates the need for PI coating, pre-baking, and post-baking steps, significantly simplifying the fabrication process while maintaining alignment functionality through the protrusion-based alignment mechanism
Solution Approach 2:
The patent creates localized alignment regions through alignment protrusions that are selectively formed at specific positions on the substrate. These protrusions provide local alignment fields that guide liquid crystal molecule orientation without requiring a complete PI film coverage, thereby reducing process complexity while achieving reliable alignment at critical locations
2Device complexity
If PI-less technologies with alignment protrusions are used, then the fabrication process complexity is reduced, but the response speed becomes slow and light leakage occurs at the alignment protrusion regions
Solution Approach 1:
The patent employs a composite structure combining alignment protrusions with polymer stabilization layers. The protrusions provide mechanical alignment guidance while the polymer layers (formed from monomers with different functional groups) provide optical stabilization and prevent light leakage. This composite approach maintains the simplified fabrication process while improving response speed and contrast ratio
Solution Approach 2:
The patent modifies the physical and chemical parameters of the alignment structure by using protrusions with specific height, shape, and distribution patterns. Additionally, polymer monomers with different functional groups are used to control polymerization characteristics, optimizing the alignment and optical properties to eliminate light leakage and improve response speed while maintaining process simplicity
3Ease of manufacture
If only vertical alignment of liquid crystal molecules is achieved, then the alignment protrusions can be used, but the response speed is slow and contrast ratio decreases due to light leakage
Solution Approach 1:
The patent segments the alignment function into two distinct components: alignment protrusions that provide initial vertical alignment guidance, and polymer stabilization layers that lock in the alignment and prevent light leakage. This segmentation allows each component to be optimized independently, achieving both ease of manufacture and high reliability in terms of response speed and contrast ratio
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
This approach enhances the response speed and contrast ratio of PSA-LCD panels by vertically aligning and pre-tilting liquid crystals, improving performance without complicating the fabrication process.
Implementation Method 1
polymerizing the monomer with single functional group to form two alignment films on inner surfaces of the first substrate and the second substrate
Implementation Method 2
polymerizing the monomer with multiple functional groups to form polymers on inner surfaces of the alignment films to pre-tilt the liquid crystal molecules
Data Source
AI summary
A method for fabricating a polymer stabilized alignment liquid crystal display panel including: filling a liquid crystal layer between a first substrate and a second substrate, the liquid crystal layer including liquid crystal molecules, monomer with single functional group and monomer with multiple functional groups; polymerizing the monomer with single functional groups to form two alignment layers over inner surfaces of the first substrate and the second substrate; and polymerizing the monomer with multiple functional groups to form a polymer capable of pre-tilting the liquid crystal molecules.