OLED Array Substrate Layout for Embedded Fingerprint Sensing
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Solution Overview
Problem
OLED display panels face challenges in embedding self-capacitive fingerprint-recognition sensors due to their common electrode layers, which hinder effective fingerprint recognition.
Innovation Solution
A method for fabricating an array substrate that includes forming a driving-circuit layer, a first electrode layer, a pixel-defining layer, an organic light-emitting layer, and a second electrode layer, with the second electrode layer being divided into a common electrode and fingerprint-recognition electrodes using pattern-defining layers, allowing for the integration of self-capacitive fingerprint-recognition sensors within the OLED display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common electrode layer is used in OLED display panels, then the display structure is simplified and manufacturing is easier, but self-capacitive fingerprint-recognition sensors cannot be effectively embedded
Solution Approach 1:
The common electrode layer is segmented into two separate electrode layers: a first electrode layer (pixel electrodes) and a second electrode layer (common electrode and fingerprint-recognition electrodes). This segmentation allows the fingerprint-recognition electrodes to be independently formed and patterned, enabling self-capacitive fingerprint sensor integration while maintaining the simplified OLED structure.
Solution Approach 2:
The patent introduces a vertical dimension by forming the fingerprint-recognition electrodes in a separate layer (second electrode layer) above the pixel electrodes, with connecting via holes providing vertical electrical connection. This multi-layer vertical structure enables fingerprint recognition functionality without compromising the horizontal display performance.
2Adaptability or versatility
If the second electrode layer is divided into common electrode and fingerprint-recognition electrodes, then self-capacitive fingerprint-recognition sensors can be embedded, but the manufacturing process becomes more complex
Solution Approach 1:
The second electrode layer is segmented into common electrode regions and fingerprint-recognition electrode regions, separated by a second pattern-defining layer. This segmentation allows independent patterning and formation of each electrode type, enabling fingerprint sensor integration while maintaining manageable manufacturing complexity through systematic process design.
Solution Approach 2:
The first pattern-defining layer is formed preliminarily to define pixel openings and connecting via holes before forming the organic light-emitting layer. This preliminary action ensures proper alignment and electrical connection pathways are established early in the process, simplifying subsequent manufacturing steps.
3Reliability
If connecting via holes are formed to expose transferring electrode, then electrical connection is achieved, but the structure becomes more complex and manufacturing precision requirements increase
Solution Approach 1:
The connecting via holes are formed preliminarily through the pixel-defining layer and first pattern-defining layer to expose the transferring electrode before forming the organic light-emitting layer. This preliminary action ensures precise alignment and electrical connection pathways are established early, improving reliability while managing manufacturing precision requirements through systematic process design.
Solution Approach 2:
The transferring electrode acts as an intermediary element, electrically connecting the pixel electrode (through pixel openings) and the common electrode (through connecting via holes). This intermediary structure ensures reliable electrical connection while simplifying the overall manufacturing process by providing a dedicated connection pathway.
Data Source
AI summary
A method for fabricating an array substrate, comprising: providing a base substrate; forming a driving-circuit layer, which comprises first driving circuits and second driving circuits; forming a first electrode layer, which comprises transferring electrodes electrically connected to the first driving circuits, and pixel electrodes electrically connected to the second driving-circuits; forming a pixel-defining layer, which is provided with pixel openings and connecting via holes; forming a first pattern-defining layer, which covers the connecting via holes and exposes the pixel openings; forming an organic light-emitting-material layer, which covers the pixel openings and the first pattern-defining layer; removing the first pattern-defining layer, such that the organic light-emitting-material layer forms an organic light-emitting layer; forming a second pattern-defining layer surrounding the connecting via holes; and forming a second electrode layer, which comprises a common electrode and fingerprint-recognition electrodes isolated by the second pattern-defining layer.