Pixel Circuit Calibration for MLED Current Offset Compensation
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Solution Overview
Problem
Conventional MLED display panels suffer from working current offsets due to threshold voltage drift and differences in K values of thin-film transistors, leading to display abnormalities.
Innovation Solution
A pixel circuit incorporating a switch transistor, driving transistor, compensation transistor, and calibration module, with a compensation phase to calibrate the potential of the second node and compensate the potential of the third node, addressing potential deviations between the gate and source of the driving transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MLED display panels are used without compensation mechanisms, then the device complexity is low, but the working current accuracy deteriorates due to threshold voltage drift and K value differences
Solution Approach 1:
The patent applies preliminary action by performing potential calibration of the second node and potential compensation of the third node before the light-emitting device operates. The calibration module calibrates the potential difference caused by threshold voltage drift and K value differences in advance, ensuring accurate working current from the start of operation, thereby improving working current accuracy without requiring continuous adjustment mechanisms
Solution Approach 2:
The patent introduces a calibration module and compensation transistor as intermediary components between the data input terminal and the light-emitting device. These intermediaries actively correct the potential differences caused by transistor parameter variations, serving as mediators that ensure accurate current delivery to the light-emitting device while isolating it from the effects of threshold voltage drift and K value differences
2Stability of the object's composition
If threshold voltage compensation is implemented, then the display uniformity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements feedback through the calibration module that measures and compensates for potential differences at the second and third nodes. By continuously monitoring and correcting the potential variations caused by threshold voltage drift and K value differences, the system achieves improved display uniformity across different pixels and operating conditions, effectively compensating for manufacturing variations in transistor parameters
Data Source
AI summary
A pixel circuit and a display panel are provided, including a switch transistor, a driving transistor, a compensation transistor, and a calibration module. During a compensation phase, the calibration module calibrates the potential at a second node, while the compensation transistor compensates for the potential at a third node. By incorporating the compensation transistor and the calibration module within the pixel circuit, this allows for the compensation transistor to compensate the potential of the third node and the calibration module to compensate the potential of the second node during the compensation phase, achieving potential compensation of both the gate and the source of the driving transistor. This solves the problem of deviation in the potential difference between the gate and the source of the driving transistor, improves the accuracy of the wording current flowing into the light-emitting device, and enhances the display quality of the display panel.