OLED Display Through-Hole Sealing for Moisture Barrier Reliability
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Solution Overview
Problem
Existing organic EL display devices face challenges in maintaining the reliability of light-emitting elements due to moisture and oxygen ingress through through-holes in the display region, leading to degradation and reduced performance.
Innovation Solution
The display device incorporates a substrate with a display region containing pixels, a thin film transistor, a protective film made of a first inorganic insulating material, a sealing film made of a second inorganic insulating material, and through holes that pass through the substrate and sealing film. The second inorganic insulating material is in direct contact with the protective film in a region between the through hole and the pixels, creating a moisture and oxygen barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If through-holes are introduced in the display region for design flexibility, then adaptability is improved, but moisture and oxygen ingress occurs leading to reduced reliability
Solution Approach 1:
The sealing structure is divided into multiple segments: a first sealing layer that seals the through-hole from the display region side, and a second sealing layer that seals the through-hole from the back side. This segmentation allows the through-hole to maintain design flexibility while being protected by separate sealing mechanisms at different locations.
Solution Approach 2:
Sealing layers are introduced as intermediary structures between the through-hole and the light-emitting elements. These sealing layers act as barrier mediators that prevent direct contact between moisture/oxygen from the through-hole and the sensitive light-emitting elements, thus maintaining both design flexibility and reliability.
2Ease of manufacture
If conventional sealing structures are used, then manufacturing simplicity is maintained, but moisture and oxygen barrier performance is insufficient
Solution Approach 1:
The patent employs thin film sealing layers formed by deposition processes. These thin film structures provide effective moisture and oxygen barrier performance while being compatible with existing thin-film transistor manufacturing processes, thus maintaining ease of manufacture while improving barrier performance.
Solution Approach 2:
The sealing structure uses composite material layers including inorganic insulating materials and organic insulating materials. This composite approach combines the advantages of different materials: inorganic materials provide excellent barrier properties against moisture and oxygen, while organic materials provide good adhesion and flexibility, achieving both ease of manufacture and superior barrier performance.
Data Source
AI summary
A display device includes a substrate, a plurality of pixels above the substrate, each of the pixels including a light emitting element, a display region including the plurality of pixels, a thin film transistor which each of the plurality of pixels includes, a protective film including a first inorganic insulating material and located between the thin film transistor and the light emitting element, a sealing film including a second inorganic insulating material and covering the light emitting element, and at least one through hole located in the display region and passing through the substrate, the protective film, and the sealing film, wherein the second inorganic insulating material is in direct contact with the protective film in a first region located between the through hole and the pixels.