AMOLED Sub-Pixel Shielding Capacitor Layout for Flicker Reduction
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Solution Overview
Problem
In AMOLED display devices, the instability of gate voltage in sub-pixel driver transistors leads to inconsistent durations for anode voltages of different colors to reach a stable state, causing deviations in brightness and chromaticity, resulting in screen flickering.
Innovation Solution
A display substrate with sub-pixels featuring a double-gate structure compensation transistor and a shielding pattern that forms a shielding capacitor, where the overlap area between the shielding pattern and conductor pattern varies between sub-pixels to set specific capacitance values, ensuring uniform leakage and stable voltage states across sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-gate transistor structure is used in sub-pixel driver circuits, then the device complexity is low, but the gate voltage stability deteriorates causing screen flickering
Solution Approach 1:
The transistor gate is divided into two separate gates (first gate and second gate) instead of a single gate. The first gate receives the gate signal while the second gate is connected to the shielding pattern, creating a double-gate structure that segments the original gate function to improve voltage stability and reduce interference.
Solution Approach 2:
A shielding pattern is introduced as an intermediary element between the power signal line and the transistor. This shielding pattern forms a shielding capacitor with the conductor pattern, acting as a mediator to block interference from the power signal line and stabilize the gate voltage.
2Reliability
If the overlap area between shielding pattern and conductor pattern is made large, then the shielding capacitance increases improving voltage stability, but the sub-pixel area increases
Solution Approach 1:
The overlap area between the shielding pattern and conductor pattern is adjusted locally for different sub-pixels based on their specific requirements. First sub-pixels have a larger overlap area to provide stronger shielding, while second sub-pixels have a smaller overlap area, optimizing the balance between shielding effectiveness and area utilization for each sub-pixel type.
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 ensures consistent stable states for anode voltages across sub-pixels, reducing screen flickering and improving display image quality by setting suitable capacitance values for each sub-pixel.
Implementation Method 1
a shielding pattern electrically coupled with the power signal line in the sub-pixel which is adjacent the shielding pattern in a second direction; wherein there is an overlap area between an orthographic projection of the shielding pattern onto the base substrate and an orthographic projection of the conductor pattern onto the base substrate
Implementation Method 2
the sub-pixels include multiple first sub-pixels and multiple second sub-pixels; the overlap area in the first sub-pixel is greater than the overlap area in the second sub-pixel
Data Source
AI summary
The present application provides a display substrate and a method for manufacturing the same and a display device. In the display substrate, each sub-pixel includes: a power signal line; sub-pixel driver circuits and a shielding pattern. The sub-pixel driver circuit includes a driver transistor and a compensation transistor of double-gate structure. The shielding pattern is electrically coupled with the power signal line in the sub-pixel which is adjacent the shielding pattern in a second direction. There is an overlap area between an orthographic projection of the shielding pattern onto the base substrate and an orthographic projection of the conductor pattern onto the base substrate; the second direction intersects the first direction. The sub-pixels include multiple first sub-pixels and multiple second sub-pixels; the overlap area in the first sub-pixel is greater than the overlap area in the second sub-pixel.