Display Panel Overhang Encapsulation for Narrow-Bezel Moisture Protection
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Solution Overview
Problem
Display devices are vulnerable to penetration of external moisture and oxygen, which can lead to improper operation and damage, and there is a need for a display device that prevents such penetration while maintaining a narrow bezel and low power consumption.
Innovation Solution
A display device design featuring a substrate with a display area and dam area, a planarization layer, an emission layer, an outermost bank, and overhang structures that overlap with each other, along with a cathode layer and encapsulation layers to prevent moisture and oxygen ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulation layers and overhang structures are added to prevent moisture and oxygen penetration, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements nested encapsulation structures where multiple encapsulation layers are stacked one on top of another, with each layer providing additional protection. The overhang structures are formed by extending material layers beyond the active display area and then patterning them to create protective overlaps. This nested arrangement maximizes protection against moisture and oxygen while maintaining a compact overall structure.
Solution Approach 2:
The protective structure is divided into multiple functional segments: the emission layer for light generation, multiple encapsulation layers for environmental protection, and overhang structures for additional sealing. Each segment has a specific function, and their modular arrangement allows for optimized protection without requiring a single complex monolithic structure.
2Productivity
If the bezel is made extremely narrow to improve display area ratio, then productivity is improved, but reliability deteriorates due to increased vulnerability to moisture and oxygen
Solution Approach 1:
Instead of increasing the lateral bezel width to improve protection, the patent extends protection into the vertical dimension by adding multiple encapsulation layers stacked above the display area. The overhang structures also extend in the vertical dimension, creating a three-dimensional protective barrier that protects the narrow bezel area without compromising the display area ratio.
Solution Approach 2:
Multiple encapsulation layers are nested within each other, with each layer providing an additional barrier against moisture and oxygen. This nested arrangement creates a compact protective structure that can be added to the narrow bezel area without significantly increasing the overall device footprint or compromising the display area ratio.
3Reliability
If multiple encapsulation layers and overhang structures are added to prevent moisture and oxygen ingress, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The overhang structures are formed by extending material layers beyond the active display area during the manufacturing process, and then patterning them to create the desired protective overlaps. This preliminary extension and subsequent patterning approach ensures proper alignment and positioning of the overhang structures relative to the display area, reducing the precision requirements during final assembly.
Solution Approach 2:
The formation of overhang structures is merged with the encapsulation layer deposition process, where material layers are deposited and patterned in an integrated manner. This combining of processes reduces the number of separate manufacturing steps and improves alignment precision by ensuring that all structures are formed in a coordinated sequence within the same manufacturing environment.
Data Source
AI summary
A display device in one example includes a planarization layer disposed on a substrate, an emission layer disposed on the planarization layer in the display area, an outermost bank disposed on the planarization layer in the dam area, a first overhang structure disposed to overlap with the outermost bank, and a second overhang structure disposed to overlap with the first overhang structure. The display device can prevent the penetration of external moisture or oxygen.