Liquid Crystal Display Panel Seal Line Adhesion
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Solution Overview
Problem
The challenge in liquid crystal display panels is the introduction of moisture or humidity through the interface between the polyimide-based liquid crystal alignment layer and the seal line, leading to corrosion and separation of the TFT substrate and the opposite substrate, especially when the bezel region width is minimized.
Innovation Solution
A liquid crystal display panel design with a polyimide-based liquid crystal alignment layer featuring a first and second region, where the second region has increased surface roughness and hydrophilic group content, and is selectively treated with hydrophilic surface methods like atmospheric plasma or UV ozone treatment, overlapping with the seal line to enhance adhesion and moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the width of the bezel region is decreased to reduce the area of the liquid crystal display panel, then the area of the panel is reduced, but moisture or humidity may be introduced into the panel through the interface between the alignment layer and seal line, causing corrosion and separation
Solution Approach 1:
The patent applies local quality by creating a second region in the alignment layer with different properties (higher surface roughness and hydrophilic group content) specifically at the peripheral portion that contacts the seal line, while the first region maintains standard properties for normal alignment function. This localized modification enhances moisture resistance at the critical interface without affecting the overall panel area or display region.
Solution Approach 2:
The patent changes physical and chemical parameters of the alignment layer by increasing surface roughness (from Ra 1.5nm to 3.0nm or higher) and hydrophilic group content (carboxyl groups) in the second region. These parameter changes improve adhesion and moisture resistance at the seal line interface, allowing the bezel width to be minimized while maintaining reliability.
2Length of stationary object
If the width of the seal line is decreased to minimize the bezel region, then the bezel width is reduced, but the adhesion between the seal line and alignment layer may be insufficient, allowing moisture penetration
Solution Approach 1:
The patent creates a localized second region with enhanced surface properties (roughness and hydrophilicity) specifically where the seal line contacts the alignment layer. This local modification strengthens adhesion at the critical interface, allowing the seal line width to be minimized without compromising bonding strength.
Solution Approach 2:
The patent performs preliminary surface treatment (plasma treatment, UV irradiation, or chemical treatment) on the alignment layer to create the second region with enhanced adhesion properties before applying the seal line. This preliminary action ensures strong adhesion is established in advance, enabling the use of narrower seal lines while maintaining bonding strength.
3Area of stationary object
If the interface between the alignment layer and seal line is minimized to reduce bezel width, then the bezel region is minimized, but the interface becomes more susceptible to moisture introduction
Solution Approach 1:
The patent applies local quality by creating a second region with enhanced moisture resistance properties (higher surface roughness and hydrophilic group content) specifically at the peripheral portion of the alignment layer that forms the interface with the seal line. This localized modification protects the minimized interface from moisture penetration while maintaining narrow bezel width.
Solution Approach 2:
The patent converts the potential harm of the alignment layer's hydrophobic nature (which normally repels liquid crystal) into a benefit by selectively increasing hydrophilic groups in the second region. This converts the interface from a moisture-vulnerable area to a moisture-resistant barrier, allowing the bezel width to be minimized without increasing moisture susceptibility.
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 design improves the interfacial adhesion and moisture-proofing, preventing moisture penetration and maintaining the stability and reliability of the display panel with a narrow bezel region, thereby ensuring improved display quality and panel integrity.
Implementation Method 1
selectively performing hydrophilic surface treatment on only a second region of first and second regions of a liquid crystal alignment layer including a polyimide
Implementation Method 2
hydrophilic surface methods like atmospheric plasma or UV ozone treatment
Implementation Method 3
improves the interfacial adhesion and moisture-proofing, preventing moisture penetration
Data Source
AI summary
A liquid crystal display panel includes substrates opposed to each other, a liquid crystal layer interposed between the substrates, a seal line surrounding an outer peripheral portion of the liquid crystal layer and disposed between the substrates and a liquid crystal alignment layer including a polyimide, the liquid crystal alignment layer including a first region and a second region disposed in an outer peripheral portion of the first region and disposed on one surface of at least one of the substrates, wherein at least a portion of the second region is overlapped with the seal line, the second region having a surface roughness value greater than that of the first region.