Organic Light-Emitting Display Device With Layered Gate Electrode
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Solution Overview
Problem
In organic light-emitting display devices, signal distortion due to line resistance in metal wires leads to uneven luminance and reduced reliability, as signals supplied to pixels far from the source are affected.
Innovation Solution
The design includes a thin film transistor with a gate electrode on a different layer than the scan line, an active layer made of oxide semiconductor, and a capacitor with electrodes on various layers, along with low resistance scan lines and insulating layers to reduce RC load and increase aperture ratio, while the capacitor is formed with multiple electrodes to minimize area and maximize capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal wires are used for scan lines, data lines, and power lines, then electrical connection is achieved, but line resistance causes signal distortion and uneven luminance
Solution Approach 1:
The patent divides the electrical connection system into multiple layers with scan lines on the first substrate and gate electrodes on the second substrate, separating different functional components to reduce interference and resistance effects in signal transmission
Solution Approach 2:
The patent transitions from planar wiring to three-dimensional stacked architecture, placing scan lines and gate electrodes on different layers connected through contact holes, thereby reducing line resistance and improving signal transmission quality
2Ease of manufacture
If gate electrode and scan line are on the same layer, then manufacturing is simplified, but RC load increases and aperture ratio decreases
Solution Approach 1:
The patent positions the gate electrode on a different layer (second substrate) than the scan line (first substrate), connecting them through contact holes. This vertical separation reduces RC load while maintaining manufacturing feasibility through aligned contact hole formation
Solution Approach 2:
The contact holes are formed by sequentially penetrating insulating layers to connect the scan line to the gate electrode, creating a nested structure that simplifies the overall manufacturing process while reducing electrical resistance
3Reliability
If capacitor occupies large area, then capacitance increases, but aperture ratio decreases
Solution Approach 1:
The patent forms the capacitor using vertical stacking with first, second, and third capacitor electrodes on different layers, connected through contact holes. This three-dimensional configuration increases capacitance while minimizing the horizontal area occupied, thereby maintaining high aperture ratio
Data Source
AI summary
An organic light-emitting display device may include a plurality of scan lines, a plurality of data lines, and a plurality of pixels located at an intersection region of the scan line and the data line, wherein the organic light-emitting display device includes a thin film transistor including a gate electrode on a different layer than a scan line, an active layer on the gate electrode, and source and drain electrodes that are in contact with source and drain regions of the active layer, and a capacitor including a first capacitor electrode on the same layer as the scan line, a second capacitor electrode on the gate electrode, and a third electrode on the same layer as the source and drain electrodes.