OLED Pixel Circuit Power Line Network for Mura Reduction
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Solution Overview
Problem
The Mura phenomenon occurs in OLED displays due to resistance drop along power lines, causing current and luminance differences across pixels, leading to perceived defects in image display.
Innovation Solution
A voltage driving pixel circuit with switching circuits composed of thin film transistors is introduced to connect adjacent power lines, forming a network power line voltage structure during the light emitting phase, thereby minimizing voltage changes and resistance drops across rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power lines are used to supply voltage to pixels in OLED displays, then power delivery is achieved, but resistance drop along the power lines causes voltage variation across different pixel areas
Solution Approach 1:
Multiple power lines (first power line, second power line, third power line) are merged through switching circuits to form a unified power supply network. This allows pixels to draw power from multiple sources, reducing the impact of resistance drop in any single power line and improving voltage uniformity across the display.
Solution Approach 2:
The patent employs dynamic switching between different power lines based on timing signals. During different time periods, different power lines are activated to supply power to pixels, enabling the system to adaptively compensate for resistance drop effects and maintain consistent voltage levels.
2Device complexity
If separate power lines are used for each row of pixels, then power distribution is simplified, but lateral resistance distribution causes current differences and Mura phenomenon
Solution Approach 1:
Switching circuits act as intermediary components between multiple power lines and pixels. These switching circuits dynamically connect pixels to different power lines based on timing signals, mediating the power distribution to compensate for lateral resistance effects and eliminate the Mura phenomenon.
Solution Approach 2:
The patent changes the temporal parameter of power supply by using different time periods to activate different power lines. This time-based parameter change allows the system to compensate for resistance drop effects that would otherwise cause Mura phenomenon in spatially distributed pixels.
3Manufacturing precision
If switching circuits are added to connect multiple power lines, then voltage uniformity is improved, but circuit complexity increases
Solution Approach 1:
The power supply function is segmented into multiple independent power lines, each operating during specific time periods. Switching circuits control the segmentation and recombination of these power lines, allowing complex voltage uniformity control to be achieved through modular, time-separated operations rather than a single complex continuous system.
Data Source
AI summary
The present disclosure relates to a voltage driving pixel circuit, a display panel and a driving method thereof. The voltage driving pixel circuit comprises: any two power lines and a load connected in each power line, wherein there is one or more switching circuits between the any two power lines. By means of the voltage driving pixel circuit of the present disclosure, the power lines form a network structure in the light emitting phase, so as to avoid voltage change of the power line voltage Vdd of each row in the pixel in the light emitting phase, thereby improving lateral resistance drop and crosstalk phenomenon of the variable power line voltage Vdd.