Pixel Circuit Threshold Compensation for OLED Uniformity
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Solution Overview
Problem
Existing pixel circuits in organic light-emitting diode display panels face challenges in achieving uniform display brightness due to limited compensation time for threshold voltage, resulting in uneven image quality.
Innovation Solution
The proposed pixel circuit includes an initialization module, first and second storage modules, a drive module, a data write module, a first light-emitting control module, and a light-emitting module, where the initialization module writes an initialization voltage to the control terminal of the drive module in both initialization and compensation stages, allowing for independent threshold compensation and data writing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a manner of compensating a threshold voltage of a pixel circuit is used to improve the uniformity of the brightness, then the uniformity of display brightness is improved, but the compensation time is limited resulting in a relatively small compensation range
Solution Approach 1:
The pixel circuit is divided into multiple independent modules: initialization module, first storage module, second storage module, drive module, data write module, first light-emitting control module, and light-emitting module. This segmentation allows the compensation process to be separated into distinct phases (initialization stage and compensation stage), enabling extended compensation time without affecting other circuit operations. The initialization module can continuously write initialization voltage to the control terminal during the compensation stage, independent of the data write process.
Solution Approach 2:
The initialization module performs preliminary action by continuously writing initialization voltage to the control terminal of the drive module during the compensation stage before the data write operation. This preliminary compensation action ensures that the threshold voltage is fully compensated within an extended time range, allowing the drive module to operate with corrected characteristics before receiving the actual data voltage, thereby achieving complete compensation without limiting the compensation range.
2Manufacturing precision
If the compensation time is extended to increase the compensation range, then the uniformity requirement can be satisfied, but the circuit complexity increases
Solution Approach 1:
The initialization module serves multiple functions: it initializes the drive module during the initialization stage, continuously compensates the threshold voltage during the compensation stage, and can be integrated with the data write process. The first storage module and second storage module work together to store different voltages (control terminal voltage and light-emitting module voltage) while sharing the same initialization module. This multi-functionality allows extended compensation range without proportionally increasing circuit complexity, as the same modules perform multiple tasks across different stages.
Solution Approach 2:
The initialization process and compensation process are merged into a unified initialization module that operates continuously across both the initialization stage and compensation stage. The first storage module and second storage module are combined in the same pixel circuit with shared control terminals, allowing simultaneous voltage storage and compensation operations. This merging reduces the need for separate dedicated circuits for each function, achieving extended compensation capability while controlling overall circuit complexity.
Data Source
AI summary
A pixel circuit, a driving method of a pixel circuit, and a display panel. The pixel circuit includes an initialization module, a first storage module, a second storage module, a drive module, a data write module, a first light-emitting control module and a light-emitting module. The first light-emitting control module is connected between a first power supply and a first terminal of the drive module, the data write module is connected between a control terminal of the drive module and a data line, the light-emitting module is connected between a second terminal of the drive module and a second power supply, and the initialization module is configured to write an initialization voltage to the control terminal of the drive module and the light-emitting module in an initialization stage, and continuously write the initialization voltage to the control terminal of the drive module in a compensation stage.