OLED Display Data Line Parasitic Capacitance Reduction
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Solution Overview
Problem
OLED displays suffer from horizontal and vertical line defects due to parasitic capacitance and lack of load maintenance in the data line, caused by the overlap of driving voltage and data lines in the same layer, leading to luminance deviations and defects in image display.
Innovation Solution
The OLED display incorporates a substrate with a scan line, data line, and driving voltage line, featuring a driving transistor with a driving gate electrode, source electrode, and drain electrode, along with holding capacitors formed by overlapping electrodes to minimize parasitic capacitance and maintain load, thereby reducing defects. The data line includes a current data line and an adjacent data line separated to form holding capacitors, and the driving source electrode overlaps the driving voltage line to create additional capacitors, ensuring proper voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the data line and driving voltage line are formed in the same layer and overlap each other, then the load on the data line is maintained, but parasitic capacitance is generated between the driving gate node and data line causing horizontal line defects
Solution Approach 1:
The patent separates the data line and driving voltage line into different layers (first data line in first layer, first driving voltage line in second layer) to eliminate parasitic capacitance while maintaining load through a different mechanism (expansion of driving voltage line in the same layer as data line)
2Device complexity
If the driving voltage line and data line are formed in the same layer, then the structure is simplified, but the driving voltage line and data line cannot overlap to maintain predetermined load causing vertical line defects
Solution Approach 1:
The patent uses multi-layer structure to allow both data line and driving voltage line to coexist without interference, with the expansion portion providing the necessary overlap for load maintenance in a different spatial arrangement
3Reliability
If the data line is separated into current data line and adjacent data line, then holding capacitors are formed to maintain load, but device complexity increases
Solution Approach 1:
The adjacent data line serves dual purposes: transmitting data signal to adjacent pixel and forming holding capacitor with driving drain electrode, thereby maintaining load on current data line while performing its primary function
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 minimizes horizontal and vertical line defects by maintaining a predetermined load on the data line and shielding parasitic capacitance, resulting in improved luminance uniformity and display quality.
Implementation Method 1
the driving drain electrode overlaps a portion of the data line to form a first holding capacitor
Implementation Method 2
a second storage electrode overlapping a first storage electrode as a driving gate electrode
Data Source
AI summary
An organic light-emitting diode display is disclosed. In one aspect, the display includes a substrate, a scan line formed over the substrate and configured to provide a scan signal, and a data line crossing the scan line and configured to provide a data voltage. A driving voltage line crosses the scan line and is configured to provide a driving voltage. The display also includes a switching transistor electrically connected to the scan line and the data line and a driving transistor electrically connected to the switching transistor and including a driving gate electrode, a driving source electrode, and a driving drain electrode. The display further includes a storage capacitor including a first storage electrode formed over the driving transistor and the driving gate electrode as a second storage electrode. The second storage electrode overlaps the first storage electrode in the depth dimension and extends from the driving voltage line.