OLED Pixel Circuit Voltage Compensation for Leakage-Induced Display Error
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Solution Overview
Problem
The working current of a light-emitting device in OLED display devices deviates due to leakage current, causing a potential difference between the gate and source terminals of the driving transistor, leading to abnormal display.
Innovation Solution
A compensation method is provided that involves obtaining an initial data voltage and a correlation curve between the data voltage and voltage offset of a first node, determining a target data voltage based on this correlation, and inputting the target data voltage to the sub-pixel, using a display device with a pixel circuit comprising a switching transistor, driving transistor, and light-emitting device, and a detection device to measure and correct the voltage offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a pixel circuit with a driving transistor is used in an OLED sub-pixel, then the display device can achieve low power consumption and fast response time, but leakage current causes potential deviation at the source terminal of the output transistor, leading to working current deviation and abnormal display
Solution Approach 1:
The patent applies preliminary action by measuring the voltage offset at the first node before the light-emitting device operates, and pre-calculating the compensation amount needed. The correlation curve between data voltage and voltage offset is established in advance, allowing the system to proactively compensate for leakage current effects before they cause display errors, rather than reacting after the problem occurs.
Solution Approach 2:
The patent implements feedback by measuring the actual voltage offset at the first node using a detection device, comparing it against the expected value, and using the correlation curve to determine the appropriate compensation amount. This closed-loop feedback mechanism continuously monitors and corrects for leakage current effects, ensuring display accuracy is maintained despite the presence of leakage current in the pixel circuit.
2Device complexity
If leakage current is present in the pixel circuit, then the device structure remains simple, but the potential difference between gate and source terminals of the driving transistor deviates, causing working current deviation
Solution Approach 1:
The patent introduces an intermediary approach by using a detection device to measure the voltage offset at the first node, which serves as an intermediate measurement point between the pixel circuit and the control system. The correlation curve acts as an intermediary model that translates the measured voltage offset into the appropriate compensation amount, bridging the gap between the simple circuit structure and the need for precise voltage control without adding complex circuitry.
3Ease of operation
If the voltage offset at the first node is not compensated, then the device operates with minimal control complexity, but the working current flowing into the light-emitting device deviates from the intended value
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the data voltage based on the measured voltage offset and the correlation curve. Instead of maintaining a fixed control scheme, the system modifies the voltage parameter in real-time to compensate for leakage current effects. This allows the device to maintain simple operational control while achieving accurate display performance through parameter adaptation.
Data Source
AI summary
The application relates to a display device and a compensation method thereof. The pixel circuit of the display device includes a driving transistor and a light-emitting device, which are connected to a first node. The compensation method firstly obtains the initial data voltage of a target sub-pixel, obtains and determines the voltage offset of the first node based on the initial data voltage, and determines the target data voltage of the target sub-pixel according to the initial data voltage and the voltage offset of the first node.