Density Patterned Sealing Layer for Flexible Displays
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Solution Overview
Problem
Flexible organic electroluminescence (EL) display devices face challenges with sealing layers that are prone to cracking when bent, leading to water infiltration and reduced reliability due to the lack of effective barrier properties against moisture and oxygen.
Innovation Solution
A display device with a sealing layer featuring a density pattern comprising a low density region and a high density region, formed using an inorganic insulation layer, which is applied using a roll coater to provide improved barrier properties and prevent cracking when the device is bent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing layer with high barrier properties is used to prevent water infiltration, then reliability is improved, but cracks easily occur when the flexible display device is bent
Solution Approach 1:
The sealing layer is divided into multiple layers with different densities. The low density region (first region) and high density region (second region) are segmented within the same sealing layer structure, allowing each region to perform different functions - the low density region provides flexibility and crack resistance, while the high density region provides water infiltration prevention.
Solution Approach 2:
Different regions of the sealing layer are given different local properties. The first region has lower density to provide flexibility and prevent cracking during bending, while the second region has higher density to provide superior water and oxygen barrier properties. This local differentiation allows the sealing layer to simultaneously achieve both flexibility and protection.
2Object-affected harmful factors
If the sealing layer density is increased to improve barrier properties, then water infiltration prevention is improved, but the sealing layer becomes more prone to cracking when bent
Solution Approach 1:
The sealing layer incorporates regions with different local densities to balance barrier properties and flexibility. The low density first region maintains flexibility and crack resistance, while the high density second region provides superior water infiltration prevention, resolving the contradiction between barrier performance and bend resistance.
Solution Approach 2:
The sealing layer functions as a composite structure with regions of different densities, combining the advantages of both low density (flexibility, crack resistance) and high density (water barrier) materials within a single integrated layer, achieving properties that neither homogeneous material could provide alone.
3Ease of manufacture
If a uniform density sealing layer is used, then manufacturing is simplified, but it cannot simultaneously provide both flexibility and high barrier properties
Solution Approach 1:
Rather than using a uniform density structure, the invention implements local quality variations within the sealing layer, creating first and second regions with different densities. This approach maintains manufacturing feasibility while achieving the dual performance of flexibility and high barrier properties that a uniform structure cannot provide.
Data Source
AI summary
A display device according to the present invention includes a display region arranged with a plurality of pixels, and a sealing layer covering the display region, wherein the sealing layer includes an insulation layer having a density pattern, the density pattern is a pattern including a low density region and a high density region, the low density region has the insulation layer with a lower density than an average density within the display region of the insulation layer, and the high density region has the insulation layer with a higher density than an average density within the display region of the insulation layer.