Display Device Hole Encapsulation Structure to Delay Moisture Permeation
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Solution Overview
Problem
The permeation of oxygen or moisture through the second common layer in the hole peripheral area of display devices, which significantly reduces the lifespan of the device, is a challenge.
Innovation Solution
The display device incorporates encapsulation auxiliary portions with a reverse tapered cross-section and concave portions on the interlayer insulating layer to separate the second common layer, delaying moisture and oxygen permeation. This is achieved by using encapsulation auxiliary portions with a first auxiliary layer made of negative photoresist material and a second auxiliary layer in the same layer as the second source-drain conductive layer, along with hole peripheral dams and dummy auxiliary portions to further protect the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second common layer is disposed in the hole peripheral area to cover the light emitting layer, then the light emitting element can be fully encapsulated, but oxygen or moisture can permeate through the second common layer which reduces the lifespan of the display device
Solution Approach 1:
The patent divides the second common layer into multiple segments by introducing encapsulation auxiliary portions (first auxiliary layer and second auxiliary layer) that physically separate the continuous second common layer. This segmentation creates discontinuous regions that block the permeation pathway of oxygen and moisture, preventing them from reaching the light emitting layer while maintaining the encapsulation function.
Solution Approach 2:
The encapsulation auxiliary portions act as intermediary structures between the second common layer and the hole area. These auxiliary portions (comprising negative photoresist material and conductive material) serve as barrier layers that intercept and block the permeation of harmful substances, protecting the light emitting layer without compromising the electrical connectivity or structural integrity of the device.
2Reliability
If encapsulation auxiliary portions are added to separate the second common layer, then moisture and oxygen permeation is delayed, but the device structure becomes more complex
Solution Approach 1:
The patent merges the encapsulation function with existing structural elements by forming the first auxiliary layer from negative photoresist material used in previous manufacturing steps and the second auxiliary layer from conductive material that serves both electrical and encapsulation purposes. This merging approach adds protection against permeation while utilizing already-present materials and processes, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The encapsulation auxiliary portions serve multiple functions simultaneously: the first auxiliary layer provides both structural support and permeation barrier, while the second auxiliary layer provides both electrical connectivity and encapsulation. This multi-functionality reduces the need for separate dedicated components, thereby adding protection without proportionally increasing device complexity.
3Area of stationary object
If the second common layer extends to the hole area, then complete coverage is achieved, but the permeation path for oxygen and moisture is created
Solution Approach 1:
The patent applies segmentation by introducing encapsulation auxiliary portions that divide the continuous second common layer into separate regions. This creates discontinuous coverage that maintains area extent while blocking permeation pathways, as the auxiliary portions act as interrupting barriers within the extended coverage area.
Solution Approach 2:
The patent applies local quality by making the second common layer discontinuous in specific locations (where encapsulation auxiliary portions are introduced) while maintaining continuous coverage in other areas. This localized modification creates barrier regions precisely where needed to block permeation paths without reducing overall coverage area.
Data Source
AI summary
A display device including: a substrate; a circuit layer; an element layer; and an encapsulation layer, the substrate includes: a display area; a non-display area; a hole area; and a hole peripheral area disposed between the hole area and the display area, and the circuit layer includes: an interlayer insulating layer disposed on the substrate; two or more encapsulation auxiliary portions disposed in the hole peripheral area on the interlayer insulating layer, wherein the two or more encapsulation auxiliary portions surround the hole area; and one or more concave portions disposed between the two or more encapsulation auxiliary portions, wherein the one or more concave portions are located on the interlayer insulating layer, wherein in a direction from the substrate to the interlayer insulating layer, each of the two or more encapsulation auxiliary portions has a cross-sectional shape whose width gradually narrows as it approaches the interlayer insulating layer.