Auxiliary Electrodes in OLED Switching Transistors for Image Uniformity
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Solution Overview
Problem
Existing OLED display technologies face challenges in achieving uniformity of displayed images due to threshold voltage drift in driving transistors, which current pixel compensation circuits struggle to address effectively.
Innovation Solution
The implementation of a display panel with pixel circuits that include a driving transistor, multiple switching transistors, and auxiliary electrodes forming capacitors in overlapping areas with active layers, which increases the gate capacitance of switching transistors, thereby reducing their subthreshold swing and indirectly increasing the subthreshold swing of the driving transistor, enhancing image uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel compensation circuit is used to compensate threshold voltage of driving transistor, then display non-uniformity caused by threshold voltage drift is improved, but image uniformity cannot be further improved
Solution Approach 1:
The patent changes the electrical parameters of switching transistors by introducing auxiliary electrodes that form capacitors, thereby altering the gate capacitance and subthreshold swing characteristics to achieve better image uniformity
Solution Approach 2:
The auxiliary electrodes act as intermediary elements between the gate and the active layer, forming capacitive structures that mediate the electrical characteristics of the switching transistors to improve overall display uniformity
2Manufacturing precision
If gate capacitance of switching transistors is increased, then subthreshold swing is reduced and driving transistor subthreshold swing is increased, but device structure becomes more complex
Solution Approach 1:
The auxiliary electrodes are merged with the existing gate structure of the switching transistors, forming integrated capacitor structures that increase gate capacitance without requiring completely separate components
Solution Approach 2:
The auxiliary electrodes serve multiple functions: they act as gate extensions to control the channel and simultaneously form capacitive structures to increase gate capacitance, reducing the need for additional dedicated 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 improves the uniformity of the displayed image by adjusting the subthreshold swings of transistors, leading to a more consistent image output by increasing the gate capacitance of switching transistors and consequently the driving transistor, resulting in a greater subthreshold swing and improved display uniformity.
Implementation Method 1
a capacitor is formed in an overlapping area between one of the at least two first auxiliary electrodes and an active layer in the associated switching transistor
Data Source
AI summary
The present disclosure discloses a display panel and a display device. The display panel includes pixel circuits arranged in an array. Each pixel circuit includes a driving transistor, at least two switching transistors and at least two first auxiliary electrodes arranged in a one to one relationship to the switching transistors. By electrically connecting each of the first auxiliary electrodes with a gate of a related switching transistor, the first auxiliary electrode and the gate of the corresponding switching transistor have a same potential. A capacitor can be formed between the first auxiliary electrode and the active layer, and a capacitor is formed between the gate and the active layer.