Shared Pixel Circuit for AMOLED Threshold Voltage Compensation
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Solution Overview
Problem
The existing high-end active matrix organic light emitting diode (AMOLED) displays with low temperature poly-silicon (LTPS) technology face instability in threshold voltage of thin film transistors, leading to unstable current for OLED devices and decreased display quality, making it challenging to further reduce pixel pitch and increase pixel density.
Innovation Solution
A pixel circuit comprising a first and second pixel sub-circuit, an initialization module, and a data voltage writing module, which reduces the size of the pixel circuit by sharing components and signals, allowing for improved threshold voltage compensation and increased pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 6T1C pixel compensation circuit is used to stabilize threshold voltage, then display quality is improved, but pixel pitch cannot be further decreased due to the large number of TFTs and capacitors required
Solution Approach 1:
The patent merges two pixel circuits into a shared structure where common components (TFTs, capacitors, signal lines) are shared between adjacent pixels. Specifically, the initialization module, data voltage writing module, and emission control modules are shared, reducing the total component count per pixel while maintaining the 6T1C compensation functionality for threshold voltage stability.
Solution Approach 2:
The patent implements multi-functional modules that serve multiple pixels simultaneously. The initialization module initializes both pixels, the data voltage writing module writes data to both pixels, and the emission control module controls light emission for both OLEDs. This universal approach reduces the number of dedicated components per pixel.
2Quantity of substance
If TFT devices are made very small to fit six TFTs and one capacitor in one pixel, then pixel density is improved, but performance requirement of TFT devices becomes relatively high
Solution Approach 1:
By merging adjacent pixel circuits and sharing common components, the patent reduces the total number of TFTs and capacitors required per pixel area. This allows TFT devices to be larger with relaxed performance requirements while achieving high pixel density through the shared circuit architecture.
3Reliability
If more TFTs and capacitors are disposed in each pixel to achieve threshold voltage compensation, then display quality is improved, but the size of pixel circuit increases
Solution Approach 1:
The patent combines adjacent pixel circuits into a shared structure where initialization modules, data voltage writing modules, and emission control modules are shared between pixels. This merging reduces the total circuit area while maintaining the 6T1C threshold voltage compensation functionality that ensures stable current for OLED devices.
Solution Approach 2:
The patent reorganizes the pixel circuit layout by introducing shared modules that serve multiple pixels, effectively changing the dimensional arrangement from fully independent pixel units to a more compact shared architecture. This reduces the overall area occupied by pixel circuits while preserving compensation functionality.
Data Source
AI summary
The pixel circuit includes a first pixel sub-circuit , a second pixel sub-circuit, an initialization module and a data voltage writing module connected to the first pixel sub-circuit and the second pixel sub-circuit; the initialization module is connected to the reset signal terminal and the low potential terminal; the data voltage writing module is connected to a data voltage and a gate signal terminal, and is configured to firstly write a first data voltage to the first pixel sub-circuit and the second pixel sub-circuit and compensate for a driving module of the first pixel sub-circuit, and then to write a second data voltage to the second pixel sub-circuit and compensate for a driving module of the second pixel sub-circuit.