OLED Display Sealing With Local Anti-Oxidation Layer
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) in display devices are vulnerable to degradation due to oxygen and moisture permeation, leading to dark spots and increased electric resistance, which degrades display quality.
Innovation Solution
A display device design that includes a first substrate with a defined display and non-display area, featuring a thin film transistor, planarization layer, organic light emitting diode, capping layer, and an anti-oxidation layer in the non-display area to block oxygen permeation, while maintaining a moisture barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dam is disposed to enclose the adhesive filler between the bottom substrate and the top substrate, then moisture permeation from the side surface is suppressed, but the encapsulation layer is pressed by the spacer to be cracked in the vicinity of the display area, causing oxygen to flow from the outside to permeate to the organic light emitting diode
Solution Approach 1:
The patent divides the sealing structure into multiple functional regions: the dam structure for moisture sealing at the side surface, and the anti-oxidation layer specifically positioned to block oxygen permeation paths near the display area where the encapsulation layer is cracked. This segmentation allows each component to address specific harmful factors without compromising the other.
Solution Approach 2:
The anti-oxidation layer acts as an intermediary barrier between the external environment and the organic light emitting diode. It is strategically placed to intercept oxygen that would otherwise permeate through the cracked encapsulation layer, preventing direct contact between oxygen and the OLED while maintaining the overall sealing structure.
2Object-affected harmful factors
If a filler that absorbs oxygen is dispersed in the dam to partially block the inflow of oxygen, then oxygen permeation is reduced, but the ratio of moisture absorbent is relatively reduced, causing the moisture barrier characteristic to be degraded
Solution Approach 1:
The patent separates the functions of oxygen absorption and moisture absorption into different components: the dam structure maintains its moisture barrier function with moisture absorbent, while the anti-oxidation layer specifically addresses oxygen permeation. This functional segmentation allows both protective characteristics to be optimized independently without compromising each other.
Solution Approach 2:
The anti-oxidation layer is locally positioned at the specific region where oxygen permeation occurs (near the display area and encapsulation layer cracks), while the dam structure maintains its moisture barrier properties in the side surface region. This localized approach ensures that oxygen blocking does not compromise the overall moisture barrier characteristic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively suppresses oxygen ingress, minimizing OLED degradation and improving display reliability and quality by blocking oxygen while maintaining a high moisture barrier.
Implementation Method 1
When oxygen and moisture permeate the light emitting diode, layers that configure the light emitting diode may become oxidized, thereby causing a dark spot defect and increased an electric resistance
Implementation Method 2
a dam is disposed to enclose the adhesive filler between the bottom substrate and the top substrate. Therefore, the permeation of the moisture or oxygen from a side surface of the display device may be suppressed
Data Source
AI summary
A display device includes a first substrate on which display and non-display areas are defined; a thin film transistor over the first substrate at a portion corresponding to the display area; a planarization layer over the first substrate and the thin film transistor at a portion corresponding to the display area and at least a portion of the non-display area; an organic light emitting diode on the planarization layer at a portion corresponding to the display area; a capping layer at a portion corresponding to the display area and the at least a part of the non-display area to cover the planarization layer and the organic light emitting diode at a portion corresponding to the display area and the at least a part of the non-display area; and an anti-oxidation layer covering an end of the planarization layer and an end of the capping layer in the non-display area.