Inorganic Barrier Layer Discontinuity for Flexible OLED Stress Relief
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Solution Overview
Problem
Organic electroluminescence display devices face reliability issues due to the degradation of inorganic films used as barrier layers when the devices are bent, allowing moisture and oxygen to enter and deteriorate the organic electroluminescence elements.
Innovation Solution
The implementation of a discontinuous region between adjacent light emitting regions for the inorganic insulating layers and electrodes in the organic electroluminescence display device, which acts as a stress relaxation section to prevent the inorganic films from breaking and maintains the integrity of the barrier layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous inorganic barrier layer is used to protect the organic EL element, then the element is protected from moisture and oxygen, but the inorganic film cracks when the device is bent
Solution Approach 1:
The inorganic barrier layer is divided into multiple separate regions corresponding to individual pixel regions, with gaps between them. This segmentation prevents the formation of continuous stress paths that would cause cracking during bending, while each segmented region still provides effective barrier protection to its corresponding organic EL element area
Solution Approach 2:
The barrier layer structure is optimized locally for each pixel region rather than using a uniform continuous layer. The inorganic films are formed only in specific areas where they are needed for protection, with discontinuous regions between adjacent pixels that allow stress relaxation during bending while maintaining local protection quality
2Object-affected harmful factors
If the inorganic barrier layer is made continuous to ensure complete protection, then moisture and oxygen blocking is improved, but stress concentration occurs during bending
Solution Approach 1:
The continuous inorganic barrier layer is segmented into discrete regions aligned with pixel boundaries, creating gaps that act as stress relief zones. These segmented structures prevent stress concentration by breaking the continuous stress path that would otherwise form in a uniform continuous layer during bending
Solution Approach 2:
The discontinuous regions between inorganic barrier layers serve as intermediary zones that mediate between the need for protection and the need for stress relaxation. These gap regions allow the structure to accommodate bending stresses while the inorganic regions maintain their protective function
Data Source
AI summary
A display device includes a display region having a plurality of pixels, each of the plurality of pixels including a pixel electrode formed on an insulating surface, the plurality of pixels being arranged in a matrix shape, a bank covering an end of the pixel electrode, an organic layer including a light emitting layer covering respective light emitting regions on the pixel electrodes, an opposite electrode on the organic layer and the bank, and a first inorganic insulating layer on the opposite electrode, wherein each of the opposite electrode and the first inorganic insulating layer has a discontinuous region between the two adjacent light emitting regions.