Stacked Layer Sealing for Organic EL Moisture Protection
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Solution Overview
Problem
Organic electroluminescence (EL) display devices are prone to rapid degradation due to moisture and oxygen exposure, which affects their light-emission characteristics, and existing sealing techniques struggle to effectively prevent infiltration from the end face of the protection layer.
Innovation Solution
A display device with a stacked layer body comprising a first thin film, a second thin film that partly covers the first film, and a third thin film with a larger pattern that contacts the peripheral parts of the first film, forming a sealing body that shields the organic EL elements from outside air, including a buffer layer and multiple barrier layers to prevent moisture and oxygen infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a sealing technique is used to shield the major surface of the array substrate, then the protection from moisture and oxygen is improved, but the infiltration from the end face of the protection layer is not effectively suppressed
Solution Approach 1:
The invention transitions from two-dimensional planar sealing to three-dimensional stepped sealing by forming multiple protection layers at different heights. The first protection layer is formed at a first thickness, the second protection layer is formed at a second thickness greater than the first thickness, creating a stepped structure that seals the end face in the vertical dimension, effectively blocking moisture and oxygen infiltration paths.
Solution Approach 2:
The sealing structure is divided into multiple segmented protection layers instead of a single continuous layer. The first protection layer and second protection layer are formed separately with different thicknesses and patterns, creating distinct sealing zones that collectively provide comprehensive protection against harmful factors from both the major surface and end face.
2Ease of manufacture
If a single protection layer is formed to cover the organic EL elements, then the manufacturing process is simple, but the sealing performance against moisture and oxygen infiltration is insufficient
Solution Approach 1:
The single protection layer is segmented into multiple protection layers with different thicknesses and coverage areas. The first protection layer covers the major surface, while the second protection layer extends to cover the end face with greater thickness, creating a multi-zone sealing system that maintains manufacturing simplicity while significantly improving protection performance.
Solution Approach 2:
Different regions of the protection structure are assigned different thicknesses and material properties. The first protection layer has a first thickness suitable for major surface protection, while the second protection layer has a second thickness greater than the first thickness specifically at the end face region, providing locally optimized protection against moisture and oxygen infiltration.
Data Source
AI summary
A display device includes a substrate having, on a major surface thereof, a display area including a plurality of pixels for displaying an image, and a stacked layer body that is formed by stacking a first thin film, which is disposed to cover the display area, a second thin film, which partly covers the first thin film, and a third thin film, which covers the second thin film and is formed with a larger pattern than the first thin film. The third thin film contacts a peripheral part of the first thin film and covers the first thin film.