OLED Encapsulation Layer Layout Using Dual Pixel Defining Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in stably forming an encapsulation organic layer, which is crucial for maintaining the performance and longevity of light emitting display devices.
Innovation Solution
The display device incorporates a unique design of pixel defining layers with varying angles and distances to stabilize the encapsulation organic layer, ensuring it is positioned within the pixel defining layers and spaced apart from dams, with additional inorganic layers for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulation organic layer is formed using conventional pixel defining layer structures, then the manufacturing process is simple, but the encapsulation organic layer cannot be stably formed and is prone to damage and degradation
Solution Approach 1:
The pixel defining layer is segmented into multiple distinct layers: a first pixel defining layer with a first side surface and a second pixel defining layer with a second side surface. Each layer has different geometric characteristics (different angles with the substrate), allowing the encapsulation organic layer to be stably formed in the space between them without requiring complex single-layer structures
Solution Approach 2:
The first side surface of the first pixel defining layer and the second side surface of the second pixel defining layer are designed with different angles relative to the substrate. This asymmetric configuration creates a stable geometric constraint for the encapsulation organic layer, preventing damage and degradation while maintaining manufacturing feasibility
2Reliability
If the encapsulation organic layer is positioned close to the dams for compactness, then the device area is reduced, but the encapsulation organic layer becomes vulnerable to damage
Solution Approach 1:
The pixel defining layers (both first and second) serve as intermediary protective structures between the encapsulation organic layer and the dams. These intermediary layers provide geometric constraint and protection, allowing the encapsulation organic layer to be positioned compactly while reducing vulnerability to damage from the dams
3Reliability
If the pixel defining layers are formed with larger angles for better encapsulation stability, then the encapsulation organic layer is better protected, but the manufacturing precision requirements increase
Solution Approach 1:
Different regions of the pixel defining structure have different angle characteristics optimized for their specific functions. The first pixel defining layer has a first angle and the second pixel defining layer has a second angle, with each locally optimized to provide encapsulation stability while maintaining overall manufacturability
Data Source
AI summary
A display device includes a substrate having a display area and a non-display area; a first transistor that is disposed on the substrate and that overlaps the display area; a first pixel defining layer disposed on the first transistor; a first emission layer disposed in the first pixel defining layer; a second pixel defining layer that is disposed on the substrate and that overlaps the non-display area; a second emission layer disposed in the second pixel defining layer; a second electrode disposed on the first emission layer and the second emission layer; and an encapsulation organic layer disposed on the second electrode, wherein the encapsulation organic layer overlaps the first pixel defining layer and the second pixel defining layer, and an end of the encapsulation organic layer is disposed inside the second pixel defining layer.