OLED Pixel Circuitry Threshold Voltage Compensation
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Solution Overview
Problem
In OLED display technologies, variations in threshold voltages of drive transistors due to process variations and environmental changes, along with voltage drops across different pixel locations, lead to inconsistencies in drive current, affecting light emission luminance and display quality.
Innovation Solution
A pixel circuitry comprising a data write-in circuit, initialization circuit, sense circuit, capacitors, and a data signal supply circuit that determines and corrects the threshold voltage of the drive transistor, ensuring consistent drive current by compensating the original data signal based on the threshold voltage, thereby stabilizing light emission across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If threshold voltage compensation is implemented, then display uniformity is improved, but device complexity increases
Solution Approach 1:
The pixel circuit is divided into multiple functional modules: data write-in circuit, initialization circuit, sense circuit, and data signal supply circuit. Each module performs a specific function in the threshold voltage compensation process, allowing complex compensation operations to be broken down into manageable stages that can be implemented sequentially during different time periods.
Solution Approach 2:
The sense circuit performs threshold voltage sensing and measurement during the non-display period before the actual display period begins. By measuring the threshold voltage of the drive transistor in advance and storing it in the capacitor, the compensation can be applied during data writing without adding complexity to the display operation itself.
2Manufacturing precision
If threshold voltage measurement and correction is performed, then light emission luminance consistency is improved, but time consumption increases
Solution Approach 1:
The pixel circuit operation is divided into distinct periodic phases: non-display period for threshold voltage measurement and correction, and display period for light emission. During the non-display period, the sense circuit measures the threshold voltage and the data signal supply circuit performs correction. During the display period, the corrected data signal is used to drive the OLED, ensuring luminance consistency without extending the actual display time.
Data Source
AI summary
Embodiments of the present disclosure provide a pixel circuitry. The pixel circuitry includes a data write-in circuit, an initialization circuit, a sense circuit, a first capacitor, a second capacitor, a drive transistor, and a data signal supply circuit. The data write-in circuit supplies a data signal to a first node according to a first control signal. The initialization circuit supplies an initialization signal to a sense line according to a second control signal. The sense circuit couples a second node to the sense line according to the first control signal. The data signal supply circuit reads the voltage of the sense line according to a third control signal, determines a threshold voltage of the drive transistor according to the read voltage, and corrects an original data signal according to the threshold voltage to supply the corrected original data signal to the data line.