Pad Electrode Segmentation for OLED Signal Stability
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Solution Overview
Problem
The coupling characteristics between the driving circuit unit and the pad portion, as well as between the driving circuit unit and the substrate, in organic light-emitting display apparatuses are poor, limiting the durability and signal stability of these devices.
Innovation Solution
The implementation of a thin film transistor with a gate electrode insulated from the active layer, an interlayer insulating layer, and source and drain electrodes, along with a pixel electrode connected to the transistor, an intermediate layer with an emissive layer, and a pad electrode structure that includes multiple layers with viaholes for improved contact and adhesive force, enhancing the coupling between pad electrodes and stable signal supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pad portion structure is used in organic light-emitting display apparatus, then the device structure is simple, but the coupling characteristics between the driving circuit unit and the pad portion decrease
Solution Approach 1:
The pad electrode is divided into multiple separate electrodes (first pad electrode, second pad electrode, third pad electrode) instead of using a single conventional pad structure. This segmentation allows each pad electrode to be independently optimized for its specific coupling function, thereby improving overall coupling characteristics between the driving circuit unit and the pad portion.
Solution Approach 2:
The patent introduces a vertical stacking dimension by forming pad electrodes at different heights and positions (first pad electrode on substrate, second pad electrode on interlayer insulating layer, third pad electrode covering opening portion). This multi-dimensional arrangement enhances coupling characteristics by creating multiple contact points and improving signal transmission paths.
2Duration of action of stationary object
If the driving circuit unit is coupled with the pad portion using conventional methods, then the manufacturing process is simple, but the durability of the organic light-emitting display apparatus is limited
Solution Approach 1:
The first pad electrode is formed on the substrate before the active layer and gate electrode are deposited. This preliminary formation allows the pad electrode structure to be established early in the manufacturing process, ensuring proper alignment and coupling characteristics from the beginning, which improves durability without significantly complicating the overall manufacturing flow.
Solution Approach 2:
The interlayer insulating layer serves as an intermediary between the first pad electrode and the second pad electrode, providing proper insulation and structural support. This intermediary layer enables reliable coupling while maintaining manufacturability through standard thin-film deposition and patterning processes.
3Strength
If a single-layer pad electrode is used, then the manufacturing process is simple, but the adhesive force among pad electrodes decreases
Solution Approach 1:
The pad electrode is segmented into multiple layers (first, second, and third pad electrodes) with distinct functions. The first pad electrode provides base adhesion to the substrate, the second pad electrode creates vertical coupling through the interlayer insulating layer, and the third pad electrode seals and reinforces the structure. This segmentation significantly enhances adhesive force among pad electrodes.
Solution Approach 2:
The third pad electrode is formed to cover the opening portion and contact both the first and second pad electrodes, creating a nested structure where the third pad electrode encapsulates the lower electrodes. This nested arrangement enhances adhesive force by creating multiple bonding interfaces and reinforcing the overall pad electrode assembly.
Data Source
AI summary
An organic light-emitting display apparatus basically comprises a thin film transistor, an organic light-emitting device and a pad electrode, and provides an improved adhesive force between a pad portion and an electrode and a stable signal supply. A method of manufacturing the organic light-emitting display apparatus comprises mask processes for forming on a curve layer of a thin film transistor, a pixel electrode and a first pad electrode, a gate electrode and a second pad electrode, contact holes and an interlayer insulating layer, source and drain electrodes and a third pad electrode, and a pixel define layer.