Display Threshold Voltage Sensing During Vertical Blank Intervals
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Solution Overview
Problem
Existing display devices, such as organic light-emitting displays, face challenges in accurately sensing the driving characteristics of transistors in real time due to the requirement of sufficient sensing time, which prevents real-time image display.
Innovation Solution
A display device and method that includes a scan driver, data driver, sensing circuit, and controller, allowing threshold voltage sensing during a vertical blank period by measuring drain voltages at two points in time to predict and calculate threshold voltage variations of driving transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sufficient sensing time (several tens of ms) is used to saturate the source voltages of the driving transistors for accurate sensing, then the measurement precision of driving characteristics is improved, but the productivity of real-time image display deteriorates because the sensing operation cannot be performed in real time
Solution Approach 1:
The patent applies preliminary action by measuring the drain voltage of the driving transistor at an initial stage (before source voltage saturation) and using this early measurement value to predict the saturated source voltage. This allows the sensing operation to be completed in a short time without waiting for full saturation, thereby enabling real-time sensing while maintaining sufficient measurement accuracy through predictive calculation.
2Productivity
If the sensing operation is performed during the active display period, then the real-time sensing capability is improved, but the image quality deteriorates due to interference with the normal display operation
Solution Approach 1:
The patent implements periodic action by performing the sensing operation during the vertical blanking period, which occurs periodically between successive display frames. This timing allows the sensing operation to be executed regularly without interfering with the active display periods, ensuring both real-time sensing capability and uninterrupted high-quality image display.
3Measurement precision
If the sensing time is extended to ensure accurate threshold voltage measurement, then the measurement precision is improved, but the loss of time for display operation increases
Solution Approach 1:
The patent applies feedback by using the initially measured drain voltage as input to a prediction algorithm that calculates the saturated source voltage. This feedback mechanism allows the system to derive accurate threshold voltage information from early-stage measurements without requiring extended sensing time, thereby reducing time loss while maintaining measurement precision.
Data Source
AI summary
The display device of the present invention comprises: a display panel including a plurality of pixel rows; a scan driver providing a scan signal and a sensing signal to each of the plurality of pixel rows; a data driver connected to the plurality of pixel rows through a plurality of data lines; a sensing circuit connected to the plurality of pixel rows through a plurality of sensing lines; and controlling the scan driver, the data driver, and the sensing circuit.