OLED Display Panel Encapsulation with Cover Inorganic Layer
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Solution Overview
Problem
Organic light emitting display panels are vulnerable to moisture and oxygen, which can lead to damage and reduced reliability and lifetime, and existing solutions fail to effectively prevent external contamination and enhance impact resistance.
Innovation Solution
A display panel design featuring a base substrate with recessed areas, a circuit layer, an organic light emitting element, and an encapsulation layer with inorganic and organic layers, along with a cover inorganic layer that contacts the inner surfaces of openings and recesses to prevent moisture and oxygen ingress, while maintaining impact resistance and simplifying manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the organic light emitting element is exposed to the outside environment, then the manufacturing process is simplified, but moisture and oxygen can penetrate in and damage the element, reducing reliability and lifetime
Solution Approach 1:
The patent implements a nested encapsulation structure where the first encapsulation inorganic layer, second encapsulation inorganic layer, and encapsulation organic layer are arranged concentrically around the organic light emitting element. This multi-layer nested configuration provides progressive barriers against moisture and oxygen penetration while maintaining a compact structure that does not complicate the manufacturing process
Solution Approach 2:
The patent employs composite encapsulation materials including both inorganic layers (such as silicon oxide, silicon nitride, or aluminum oxide) and organic layers (such as epoxy or polyimide). This composite structure combines the advantages of inorganic materials (high barrier performance against moisture and oxygen) with organic materials (flexibility and adhesion), achieving effective protection without overly complicating the manufacturing process
2Reliability
If the encapsulation layer is made thicker to block moisture and oxygen, then reliability is improved, but impact resistance is reduced
Solution Approach 1:
The patent applies different material properties to different layers of the encapsulation structure. The inorganic layers provide high barrier performance with thin thickness for chemical protection, while the organic layer provides flexibility and shock absorption. This local differentiation of material qualities allows the encapsulation to simultaneously achieve high reliability against moisture/oxygen and good impact resistance without requiring uniform thickness increases
Solution Approach 2:
The encapsulation organic layer acts as a cushioning layer positioned between the rigid inorganic encapsulation layers. This organic layer can deform elastically to absorb impact energy before it reaches the fragile organic light emitting element, providing beforehand cushioning that protects against mechanical shock while the inorganic layers maintain their function as moisture and oxygen barriers
3Object-affected harmful factors
If a cover inorganic layer is added to contact the inner surface of the opening, then contamination prevention is improved, but device complexity increases
Solution Approach 1:
The cover inorganic layer is formed in advance to cover the opening through the insulation layers before the main encapsulation layers are deposited. This preliminary action creates a pre-formed barrier that guides the subsequent encapsulation process and ensures that the opening is sealed from the outset, preventing contamination without requiring complex multi-step processes
Solution Approach 2:
The cover inorganic layer serves multiple functions: it seals the opening through the insulation layers to prevent contamination, provides a foundation for the subsequent encapsulation layers, and contributes to the overall mechanical strength of the encapsulation structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
Data Source
AI summary
A display panel includes a base substrate including a display area surrounding a hole area, a circuit layer including insulation layers, where an opening is defined through each insulation layer to overlap the hole area, an element layer including an organic light emitting element connected to a transistor, an encapsulation layer disposed on the element layer and including first and second encapsulation inorganic layers and an organic layer, a cover inorganic layer overlapping the hole area and disposed between the first encapsulation inorganic layer and the insulation layers. A module hole is defined through the display panel, and a first groove is defined by portions of the cover inorganic layer and the first and second encapsulation inorganic layers which cover inner surface of the opening and the recess part. The cover inorganic layer contacts the inner surfaces of the opening and the recess part.