OLED Glass Sealant Asymmetric Geometry for Adhesion
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Solution Overview
Problem
The adhesion between the glass-forming sealant and the substrates in OLED display devices is inadequate, leading to peeling and cracking issues, which compromise the moisture barrier and air impermeability, thereby reducing the production rate of OLED display devices.
Innovation Solution
The glass-forming sealant is designed with specific structural features, including angled portions and varying widths, with optimized angles and distances between the substrates, and the inclusion of extension parts and protrusions to enhance adhesion and contact area, ensuring better sealing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass-forming sealant is used to package the substrates, then moisture barrier property and air impermeability are improved, but adhesion between the sealant and substrates deteriorates, causing peeling and cracking
Solution Approach 1:
The sealant structure is designed with different regions having different properties: angled portions adjacent to substrates for enhanced adhesion, a protrusion portion for mechanical interlocking, and an obtuse angled portion for sealing. This local differentiation allows each region to optimize its function - adhesion at interfaces, mechanical bonding at the protrusion, and sealing at the sealing surface.
Solution Approach 2:
The sealant cross-section employs asymmetric geometry with specific angle ranges (acute angles of 30-60° adjacent to substrates, obtuse angle of 120-150° at the sealing surface). This asymmetric design creates favorable stress distribution and contact areas, improving adhesion to substrates while maintaining sealing effectiveness, thereby resolving the contradiction between adhesion strength and moisture barrier reliability.
2Ease of manufacture
If the sealant structure is not optimized, then manufacturing is simpler, but production rate deteriorates due to peeling and cracking defects
Solution Approach 1:
Specific geometric parameters of the sealant are optimized to prevent defects: acute angles between 30-60° adjacent to substrates, obtuse angle between 120-150° at the sealing surface, and controlled width ratios (protrusion width 0.5-2 times the sealant width). These parameter specifications enable consistent manufacturing while preventing peeling and cracking, thereby maintaining both ease of manufacture and high production rate.
3Ease of manufacture
If the sealant has uniform width, then manufacturing is easier, but adhesion and sealing performance deteriorate
Solution Approach 1:
The sealant is segmented into distinct functional portions with different widths: a narrower sealant portion adjacent to substrates for adhesion, a wider protrusion portion for mechanical interlocking and stress distribution, and a controlled sealing portion. This segmentation allows each region to perform its specific function optimally, improving overall sealing performance while remaining manufacturable through standard dispensing processes.
Data Source
AI summary
An organic light emitting diode display device is provided, which comprises: a first substrate having a first surface with a first side; and a glass-forming sealant disposed thereon, adjacent to the first side and having a top surface, a bottom surface opposite to the top surface, and a middle surface therebetween. The middle surface has a first end connecting to the top surface, a second end connecting to the bottom surface and a third end therebetween. A first distance between a first projection of the first end on the first surface and the first side is unequal to a second distance between a second projection of the second end on the first surface and the first side; and a third distance between a third projection of the third end on the first surface and the first side is shorter than the first or second distance.