OLED Thin-Film Encapsulation Structure for Side Moisture Barrier
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Solution Overview
Problem
OLED displays using thin film encapsulation face challenges in preventing moisture and oxygen permeation along the side surface direction, which can degrade the organic emission layer and affect the display's quality and longevity.
Innovation Solution
The implementation of a multi-layered thin film encapsulation structure, including a first inorganic layer formed through atomic layer deposition (ALD), an intermediate layer, and a second inorganic layer, which are sequentially layered on the edge of the substrate, along with an optional upper layer, to effectively suppress moisture and oxygen permeation. This structure minimizes damage to the organic light emitting diode during the encapsulation process and simplifies the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If thin film encapsulation is used to reduce thickness and enable flexible display, then device thickness is reduced and flexibility is improved, but moisture and oxygen permeation along the side surface direction increases
Solution Approach 1:
The encapsulation structure is divided into multiple inorganic layers (first inorganic layer, second inorganic layer, third inorganic layer) with different area coverage patterns. Each layer segments the protection function to address both top-surface and side-surface barrier requirements independently, resolving the contradiction between thin film usage and side-surface moisture prevention.
Solution Approach 2:
The patent transitions from conventional single-layer encapsulation to a multi-dimensional layered structure where layers extend beyond the organic light emitting diode area. The second and third inorganic layers specifically address the side surface dimension by covering larger areas and overlapping edges, preventing moisture permeation along the thickness direction while maintaining overall thin film encapsulation benefits.
2Reliability
If multiple layers are added to prevent moisture permeation, then barrier performance is improved, but device complexity increases
Solution Approach 1:
Different inorganic layers are designed with different area coverage characteristics tailored to their specific protective functions. The first inorganic layer covers the organic light emitting diode area for top protection, while the second and third layers extend to larger areas for side surface protection. This localized differentiation optimizes barrier performance without requiring uniform complexity throughout the entire structure.
Solution Approach 2:
The encapsulation structure employs a nested arrangement where the first inorganic layer is positioned at the bottom, the second inorganic layer is formed on top with larger area coverage, and the third inorganic layer is positioned at the top with intermediate coverage. This nested configuration allows multiple protective functions to be integrated in a compact vertical arrangement, reducing overall structural complexity while maintaining effective multi-layer barrier performance.
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 solution effectively suppresses moisture and oxygen permeation along the side surface direction, maintains the quality of the organic light emitting diode, and simplifies the manufacturing process by reducing the number of masks required, thereby improving productivity and extending the display's lifespan.
Implementation Method 1
The first inorganic layer may be formed through an atomic layer deposition (ALD) method.
Implementation Method 2
the OLED display using the thin film encapsulation can effectively prevent permeation of moisture or oxygen along a direction perpendicular to the substrate
Data Source
AI summary
An organic light emitting diode (OLED) display including: a substrate; an organic light emitting diode formed on the substrate; a metal oxide layer formed on the substrate and covering the organic light emitting diode; a first inorganic layer formed on the substrate and covering the organic light emitting diode; a second inorganic layer formed on the first inorganic layer and contacting the first inorganic layer at an edge of the second inorganic layer; an organic layer formed on the second inorganic layer and covering a relatively smaller area than the second inorganic layer; and a third inorganic layer formed on the organic layer, covering a relatively larger area than the organic layer, and contacting the first inorganic layer and the second inorganic layer at an edge of the third inorganic layer.