OLED Pixel Circuit Leakage Detection for Threshold Voltage Accuracy
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Solution Overview
Problem
In display panels, particularly OLEDs, the drift of threshold voltage in pixel circuits leads to abnormal driving current output, affecting display quality due to current leakage through sensing lines, which compromises the accuracy of threshold voltage and mobility detection, thereby impacting compensation and display effect.
Innovation Solution
A display panel with a detection device that measures current leakage and characteristic parameters of driving transistors, using specific time periods and voltage inputs to obtain accurate reference and target parameters, allowing for precise compensation of data signals and improved display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal compensation or external compensation is used to solve abnormal driving current, then the driving current abnormality is addressed, but the current leakage through sensing lines compromises detection accuracy
Solution Approach 1:
The patent applies preliminary action by performing detection of current leakage parameters before the actual threshold voltage and mobility detection. The detection device first measures the current leakage through the sensing line during a first time period, then uses this information to compensate for the leakage effect in subsequent detection during a second time period. This preliminary measurement and compensation approach ensures that the main detection is not compromised by current leakage.
Solution Approach 2:
The patent introduces an intermediary approach by using a separate detection process that measures current leakage parameters independently. This intermediary detection of leakage current allows the system to quantify and compensate for the harmful effect, rather than directly attempting to eliminate the leakage itself. The leakage parameter serves as an intermediary variable that enables accurate main detection.
2Productivity
If detection is performed during display state, then real-time compensation is achieved, but current leakage affects measurement accuracy
Solution Approach 1:
The patent segments the detection process into distinct time periods: a first time period dedicated to measuring current leakage parameters, and a second time period for measuring threshold voltage and mobility parameters. This temporal segmentation allows each measurement to be optimized independently, with the leakage measurement taken when it does not interfere with the main parameter detection.
Solution Approach 2:
The patent implements periodic action by alternating between different detection modes in different time periods. During the first time period, the system periodically measures current leakage; during the second time period, it periodically measures threshold voltage and mobility. This periodic switching between detection tasks allows real-time monitoring while maintaining accuracy.
Data Source
AI summary
A display apparatus, a display panel, and a driving method thereof, and a method of detecting a pixel circuit are described. The display panel includes a pixel unit and a detection apparatus, and the pixel unit includes a pixel circuit and a light-emitting element. The pixel circuit includes a first transistor, a second transistor, a driving transistor, and a storage capacitor. The detection device is configured to: turn off the first transistor and the second transistor, and detect an amount of current leakage of the driving transistor leaked through the sensing line to obtain a first current leakage parameter; detect a first characteristic parameter of the driving transistor to obtain a first reference characteristic parameter; and determine a first target characteristic parameter according to the first current leakage parameter and the first reference characteristic parameter.