OLED Intermediate Layer Parasitic Capacitance Reduction
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Solution Overview
Problem
Organic light-emitting display apparatuses face performance deterioration due to parasitic capacitance, which causes signal delay and other issues, particularly between the opposite electrode and the signal line.
Innovation Solution
The introduction of an intermediate layer that extends over the pixel electrode and corresponds to the signal line, interposed between the signal line and the opposite electrode, reduces parasitic capacitance by forming a series connection with the first insulating layer and pixel-defining layer, thereby minimizing overall capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the opposite electrode is positioned close to the signal line to reduce device thickness, then the device structure is simplified and thickness is reduced, but parasitic capacitance between the opposite electrode and signal line increases causing signal delay
Solution Approach 1:
The patent introduces an intermediate layer positioned between the opposite electrode and the signal line. This intermediate layer acts as a mediator that reduces the parasitic capacitance between these two components while maintaining the overall device thickness. The intermediate layer is specifically positioned to overlap with the signal line, creating a series connection with the first insulating layer and pixel-defining layer, thereby minimizing the total capacitance without requiring increased spacing between the opposite electrode and signal line.
2Reliability
If the intermediate layer is extended to overlap with the signal line, then parasitic capacitance is reduced through series connection, but the device structure becomes more complex
Solution Approach 1:
The intermediate layer serves multiple functions simultaneously: it acts as part of the light-emitting structure, provides electrical insulation, and reduces parasitic capacitance by forming a series connection with the signal line. By making the intermediate layer extend beyond the pixel electrode to overlap with the signal line, a single structural element achieves multiple objectives without requiring additional separate components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively decreases parasitic capacitance, enhancing the performance and characteristics of the organic light-emitting display apparatus by reducing signal delay and improving overall display quality.
Implementation Method 1
parasitic capacitance, which causes signal delay and other issues, particularly between the opposite electrode and the signal line
Data Source
AI summary
An organic light-emitting display apparatus may include a substrate; a thin-film transistor (TFT) disposed on the substrate, and having an active layer, a gate electrode, a source electrode and a drain electrode; a signal line formed on the same layer as the source electrode and the drain electrode; a first insulating layer covers the signal line, the source electrode, and the drain electrode; a pixel electrode formed on the first insulating layer, and electrically connected to the TFT; a pixel-defining layer formed on the first insulating layer, includes an opening exposing the pixel electrode; an intermediate layer formed on the pixel electrode, and includes a light-emitting layer; and an opposite electrode formed on the intermediate layer. The intermediate layer is formed on the pixel-defining layer so as to overlap with the signal line.