OLED Encapsulation Structure for Narrow Bezel Edge Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high fabricating costs of organic light emitting diode (OLED) displays hinder their widespread adoption in display devices, and there is a need to reduce the bezel area and minimize deterioration of touch sensitivity in the edge areas of substrates.
Innovation Solution
The display device incorporates a multi-layer encapsulation structure comprising a first inorganic encapsulation layer, an organic encapsulation layer, a second inorganic encapsulation layer, and an intermediate inorganic encapsulation layer with specific geometric configurations, along with a method of fabricating the device using a mask and ashing techniques to form the encapsulation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional encapsulation structure is used, then the fabrication process is simpler, but the fabricating cost is high and the bezel area is large
Solution Approach 1:
The encapsulation layer is divided into multiple inorganic encapsulation layers and organic encapsulation layers with different functions. The first inorganic encapsulation layer provides initial protection, the organic encapsulation layer fills gaps and provides additional barrier, and the second inorganic encapsulation layer provides final protection with extended coverage. This segmentation allows each layer to be optimized for its specific function, reducing overall material usage and fabrication cost while maintaining comprehensive protection.
Solution Approach 2:
The patent extends the encapsulation coverage into the non-display area, with the second inorganic encapsulation layer having a second extension portion that reaches further toward the edge of the substrate. This dimensional extension provides enhanced protection at the edges where touch sensitivity is critical, while the selective placement of organic encapsulation layers optimizes material usage and reduces bezel area.
2Reliability
If the encapsulation layer extends to the edge of the substrate, then edge protection is improved, but touch sensitivity deteriorates
Solution Approach 1:
Different regions of the encapsulation structure have different properties and extents. The second inorganic encapsulation layer extends further in the non-display area to provide enhanced edge protection, while the organic encapsulation layer is selectively placed only in specific regions. This local differentiation ensures maximum protection where needed (edges) while maintaining touch sensitivity in the display area.
Solution Approach 2:
The organic encapsulation layer acts as an intermediary between the first and second inorganic encapsulation layers, filling gaps and providing additional barrier protection. Its selective placement in the non-display area allows it to enhance edge protection without interfering with touch sensitivity in the display area, mediating between the conflicting requirements of protection and operational sensitivity.
3Reliability
If thicker encapsulation layers are used, then durability is improved, but fabrication cost increases
Solution Approach 1:
The patent varies the thickness and extension of different encapsulation layers based on their specific functions. The second inorganic encapsulation layer has a second extension portion that extends further in the non-display area with optimized thickness for edge protection, while the organic encapsulation layer has controlled thickness to provide sufficient barrier without excessive material usage. This parameter optimization achieves maximum durability with minimum material cost.
Solution Approach 2:
The encapsulation structure uses a composite of inorganic and organic materials, each with complementary properties. The inorganic layers provide robust barrier protection against moisture and oxygen, while the organic layer provides flexible gap-filling and additional protection. This composite approach achieves superior durability with optimized material usage, as each material type is used where it provides the most benefit.
Data Source
AI summary
A display device includes a substrate, a first electrode disposed on the substrate, a light emitting layer disposed on the first electrode, a second electrode disposed on the light emitting layer and an encapsulation layer disposed on the second electrode, wherein the encapsulation layer includes a first inorganic encapsulation layer disposed on the second electrode, an organic encapsulation layer disposed on the first inorganic encapsulation layer, a second inorganic encapsulation layer disposed on the organic encapsulation layer and the first inorganic encapsulation layer and an intermediate inorganic encapsulation layer disposed between the organic encapsulation layer and the second inorganic encapsulation layer, wherein any one of the surfaces of the intermediate inorganic encapsulation layer opposing each other is in contact with the organic encapsulation layer, and wherein the other of the surfaces of the intermediate inorganic encapsulation layer opposing each other is in contact with the second inorganic encapsulation layer.