OLED Pixel Defining Layers Adhesion via Composite Structure
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in achieving strong adhesive strength between pixel defining layers, which can lead to displacement of the second pixel defining layer from its predetermined position, increasing manufacturing costs and time due to additional deposition processes required for wiring.
Innovation Solution
The implementation of a pixel defining structure with a first inorganic pixel defining layer and a second organic pixel defining layer, where the second layer has greater adhesive strength with wiring than with the first layer, eliminating the need for additional wiring deposition processes by using data wiring as the first wiring, and ensuring the second layer remains in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single pixel defining layer is used, then the manufacturing process is simple, but the adhesive strength is insufficient causing displacement
Solution Approach 1:
The pixel defining layer is divided into two separate layers: a first pixel defining layer and a second pixel defining layer. This segmentation allows each layer to perform specific functions - the first layer provides structural support while the second layer provides adhesive bonding to wiring, thereby achieving both mechanical stability and strong adhesion without requiring a single overly complex layer
Solution Approach 2:
The patent employs a composite structure where the first pixel defining layer and second pixel defining layer are made of different materials with complementary properties. The first layer may be made of inorganic material for structural stability, while the second layer is made of organic material with high adhesive properties to wiring, creating a composite system that achieves both mechanical strength and adhesion
2Strength
If additional deposition processes are added to improve adhesion, then adhesive strength increases, but manufacturing time and cost increase
Solution Approach 1:
The second pixel defining layer is designed to inherently provide adhesive bonding to the wiring structures. By selecting materials with appropriate adhesive properties for the second layer, the structure bonds to existing wiring without requiring additional deposition processes, allowing the system to achieve strong adhesion while using existing manufacturing capabilities
Solution Approach 2:
The patent changes the material parameters and adhesive properties of the pixel defining layers, particularly the second layer, to achieve strong bonding to wiring. By adjusting material composition and adhesive characteristics rather than adding process steps, the solution improves adhesion strength while maintaining manufacturing efficiency
3Length of moving object
If the second pixel defining layer is made thin, then the device structure is compact, but adhesive strength decreases
Solution Approach 1:
The patent applies different quality requirements to different layers: the first pixel defining layer is optimized for structural support and can be thicker, while the second pixel defining layer is optimized for adhesive bonding and can be thinner. This local differentiation of functional requirements allows the overall structure to be compact while maintaining sufficient adhesive strength through the specialized second layer
Data Source
AI summary
An organic light emitting display device includes, a light emitting structure, a pixel defining structure that includes first and second pixel defining layers, and a first wiring. The light emitting structure is disposed on a substrate and includes a pixel electrode, an organic light emitting layer and an opposite electrode. The first pixel defining layer is disposed on the substrate and partially covers the pixel electrode. The second pixel defining layer is disposed on the first pixel defining layer. The first wiring is disposed between the substrate and the first pixel defining layer and between the substrate and the second pixel defining layer, and is in contact with the first pixel defining layer and the second pixel defining layer. An adhesive strength between the second pixel defining layer and the first wiring is greater than an adhesive strength between the second pixel defining layer and the first pixel defining layer.