OLED Pixel Driving Circuit Threshold Voltage Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OLED display panels face challenges in distinguishing abnormal threshold voltages caused by short-circuits within pixel-driving circuits, as these voltages are close to normal threshold voltages, making it difficult to differentiate and compensate effectively.
Innovation Solution
A detection method involving repeated operations on pixel-driving circuits, where the gate voltage is incremented by the difference between the initial gate voltage and sampled voltage in each iteration, allows for the amplification of discrepancies between normal and abnormal circuits, enabling the identification of abnormal threshold voltages through comparison with a preset voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threshold voltage detection is performed on pixel-driving circuits, then compensation can be applied to reduce the impact of threshold voltage drift, but abnormal threshold voltages caused by short-circuits cannot be distinguished from normal threshold voltages
Solution Approach 1:
The patent applies periodic action by performing repeated detection operations (n times) on the pixel-driving circuits. Each repetition uses the same detection process, but the gate voltage is accumulated based on the difference between the current gate voltage and the sampled voltage from the previous operation. This periodic repetition amplifies the discrepancy between normal and abnormal circuits, enabling distinction of abnormal threshold voltages.
Solution Approach 2:
The patent implements feedback by using the sampled voltage from each detection operation to adjust the gate voltage for the next operation. The gate voltage in the current operation is set to the sum of the initial gate voltage and the accumulative addition of the difference between the gate voltage and sampled voltage from the previous operation. This feedback mechanism progressively amplifies voltage differences, making abnormal circuits distinguishable.
2Measurement precision
If repeated detection operations are performed to amplify voltage discrepancies, then abnormal pixel-driving circuits can be identified, but the detection process becomes more complex
Solution Approach 1:
The patent uses periodic action with a fixed number of repetitions (n times) to achieve reliable abnormal circuit identification. Each period follows the same structured process: apply gate voltage, sample voltage, calculate difference, and accumulate. This standardized periodic approach makes the complex detection process manageable and repeatable.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the gate voltage based on the accumulated differences from previous operations. The gate voltage in each subsequent operation changes according to the formula: gate voltage(n) = gate voltage(0) + Σ(gate voltage(i-1) - sampled voltage(i-1)). This parameter change strategy amplifies the signal difference between normal and abnormal circuits without requiring complex hardware modifications.
Data Source
AI summary
A detection method and a detection device for a display panel are provided. The detection method includes: performing a detection operation on pixel-driving circuits. The detection operation includes applying a gate voltage and a source voltage to a gate and a source of each driving transistor, to turn on a driving transistor; and sampling voltages at the sources. The detection operation is repeated n times, where in each repetition, the gate voltage is the sum of the gate voltage in the initial detection operation and an accumulative addition of a difference between the gate voltage and the sampled voltage in the previous detection operation, with n being a positive integer. Based on the sampled voltage of the driving transistor of each pixel-driving circuit obtained in the n-th repetition of the detection operation, it is determined whether the threshold voltage of the driving transistor in the pixel-driving circuit is abnormal.