Photo Alignment Material for LCD Stability
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Solution Overview
Problem
Photo alignment methods for liquid crystal display (LCD) panels face issues such as static electricity damage and contamination from rubbing fabrics, leading to visual defects and display quality deterioration, and orientation changes due to electric stress, causing brightness differences and residual images.
Innovation Solution
A photo alignment material comprising a photo alignment polymer and an organic solvent, prepared by polymerizing a diamine monomer with multiple photo reactive parts, is used to form an alignment layer that resists orientation changes under electric stress through intramolecular and intermolecular reactions upon light exposure, ensuring stable alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rubbing fabric is used to form alignment layer, then alignment layer can be formed, but static electricity buildup damages substrate patterns and causes visual defects
Solution Approach 1:
The patent replaces the mechanical rubbing process with a photoalignment process. Instead of using a rubbing fabric that causes static electricity and contamination, a photoalignment material is coated on the substrate and exposed to UV light, which photo-decomposes or photo-isomerizes the material to form the alignment layer. This substitution eliminates the harmful mechanical contact and static electricity generation while achieving the same alignment function.
2Object-affected harmful factors
If photo alignment method is used, then static electricity damage is avoided, but orientation of alignment layer changes under electric stress causing brightness difference
Solution Approach 1:
The patent modifies the chemical structure of the photoalignment material by incorporating specific functional groups (such as carboxyl groups, hydroxyl groups, or amine groups) that provide electrostatic interaction capability. These parameter changes in the material composition enable the alignment layer to maintain its orientation under electric stress through enhanced molecular interactions, thereby preventing brightness differences while maintaining the benefits of photoalignment.
3Ease of operation
If conventional photo alignment material is used, then alignment layer can be formed without mechanical contact, but brightness difference appears due to orientation change under voltage
Solution Approach 1:
The patent uses composite photoalignment materials that combine multiple functional components: photoresponsive groups for light-induced alignment, electrostatic interaction groups (such as carboxyl, hydroxyl, or amine groups) for maintaining orientation under voltage, and appropriate molecular weight and viscosity characteristics for proper coating and alignment. This composite approach enables both contactless formation and brightness uniformity by addressing multiple requirements simultaneously.
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 effectively minimizes after-image formation and improves display quality by maintaining alignment layer orientation, reducing brightness differences and enhancing the stability of liquid crystal molecule alignment under electric stress.
Implementation Method 1
irradiated with light to cause an intramolecular reaction between photo reactive parts of a photo alignment polymer, and an intermolecular reaction between photo reactive parts of adjacent photo alignment polymers
Data Source
AI summary
A photo alignment material includes a photo alignment polymer and an organic solvent. The photo alignment polymer is prepared by polymerizing a diamine monomer including at least two photo reactive parts represented by the following Chemical Formula 1.In Chemical Formula 1, R1 represents —(CH2)n—, —O(CH2)n— orR2, R3 and R4 each independently represent —H, —O(CH2)m—1—CH3 orand n and m independently represent an integer of from 1 to 8. Thus, change of the orientation of the alignment layer due to the action of an electric stress may be prevented and/or reduced. Therefore, an after—image may be reduced, and display quality is improved.