AMOLED Pixel Circuit Row-Shared Unit Threshold Compensation
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Solution Overview
Problem
Conventional AMOLED pixel driving circuits face challenges with poor threshold voltage uniformity and increased size due to the number of TFTs and capacitors, which restricts high pixel per inch (PPI) progress and affects the service life of AMOLED panels.
Innovation Solution
A pixel circuit with a row-shared unit and sub-pixel units connected through signal lines, incorporating driving compensation modules and data writing modules to compensate threshold voltages, reducing the number of TFTs within the effective display area and increasing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional 5T2C pixel driving circuit is used to implement threshold voltage compensation, then the threshold voltage uniformity is improved, but the pixel area increases and the aperture ratio decreases
Solution Approach 1:
The patent merges the row-driving light-emitting control modules into a shared unit that serves multiple sub-pixel units simultaneously. This consolidation reduces the total number of TFTs and capacitors per pixel while maintaining the threshold voltage compensation function, thereby reducing pixel area while preserving reliability
Solution Approach 2:
The row-shared unit is designed to perform multiple functions: it provides threshold voltage compensation for multiple sub-pixel units, controls light emission timing, and manages data writing operations. This multi-functionality eliminates the need for separate dedicated circuits for each sub-pixel, reducing overall pixel area while maintaining compensation performance
2Reliability
If more TFTs and capacitors are added to implement threshold voltage compensation, then the threshold voltage uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple control functions into shared row-driving light-emitting control modules that serve multiple sub-pixel units. This merging approach maintains the necessary threshold voltage compensation capability while reducing the total component count and simplifying the overall circuit architecture
Solution Approach 2:
The circuit is segmented into sub-pixel units that can be independently configured with minimal compensation components, while the row-shared unit handles the complex control functions. This segmentation allows each sub-pixel to remain simple while the shared unit provides the necessary compensation functionality
3Productivity
If the pixel size is reduced to increase PPI, then the pixel area decreases, but the aperture ratio further decreases and current density increases
Solution Approach 1:
By merging control functions into row-shared units that serve multiple sub-pixels, the patent reduces the non-light-emitting circuit area within each pixel. This allows the aperture ratio to be maintained or increased even as overall pixel size decreases for higher PPI implementations
Solution Approach 2:
The patent extracts the complex row-driving light-emitting control modules from individual sub-pixel units and places them in a shared unit. This extraction removes unnecessary components from the critical light-emitting area, enabling smaller pixel sizes with maintained or improved aperture ratios
Data Source
AI summary
In the present disclosure, it is provided a pixel circuit including a plurality of rows of pixel units and a row-shared unit, wherein each row of pixel units includes a plurality of sub-pixel units, and the row-shared unit includes a plurality of row-driving light-emitting control modules. All of the plurality of sub-pixel units included in each row of pixel units is connected to a corresponding signal line. Each row-driving light-emitting control module among the plurality of row-driving light-emitting control modules is connected to all of the sub-pixel units included in a corresponding one row of the pixel units among the plurality of rows of pixel units through the signal line, so as to provide a threshold compensation function.