Display Device Data Driver Threshold Voltage Offset Compensation
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Solution Overview
Problem
Display devices face challenges in maintaining operability after long periods of non-use, as the threshold voltage of driving transistors can become offset, leading to failure in emitting light even when a data signal with a preset voltage level is applied.
Innovation Solution
A method involving a data driver that applies a first data voltage and determines if a sensing current flows, then applies a second data voltage offset from the first, oscillates the data signal to determine the offset sign, and adjusts the voltage level to compensate for the threshold voltage offset, ensuring the display device can emit light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a data signal with a preset voltage level is applied to the data lines, then the display device can operate normally when freshly driven, but the display device fails to emit light after being unused for a long time due to threshold voltage offset
Solution Approach 1:
The patent applies a preliminary action by performing a sensing operation before normal display operation to detect threshold voltage offsets in driving transistors. The data driver senses current flow through data lines to determine offset方向和magnitude, then applies compensatory voltage adjustments before displaying actual content, ensuring the display device can operate correctly after long-term storage.
Solution Approach 2:
The patent changes the voltage parameter dynamically based on detected threshold voltage offsets. When a sensing current is detected, the system determines the offset sign (positive or negative) and applies a compensated data voltage that adjusts the original data signal voltage level, thereby compensating for the threshold voltage drift caused by aging or storage effects.
2Ease of operation
If the threshold voltage of driving transistors offsets after long term storage, then the display device cannot emit light even with preset voltage, but applying higher voltage continuously may cause other reliability issues
Solution Approach 1:
The patent implements a feedback mechanism where the data driver continuously monitors current flow in data lines to detect threshold voltage offsets. Based on the sensed current presence and direction, the system dynamically adjusts the data voltage level to apply appropriate compensation, ensuring light emission while maintaining voltage stability through closed-loop control rather than continuous high voltage application.
3Measurement precision
If a sensing current is detected to determine offset compensation, then accurate voltage adjustment can be achieved, but the operation time and complexity increase
Solution Approach 1:
The patent applies partial action by performing sensing operations only on selected data lines or during specific time periods (e.g., initialization phase or periodic maintenance) rather than continuously on all lines. This approach achieves sufficient threshold voltage offset detection accuracy for practical purposes while minimizing the time overhead and operational complexity compared to exhaustive sensing of every data line at all times.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the display device to operate correctly even after being unused for a long time by accurately determining and adjusting the data voltage levels, thereby compensating for the offset threshold voltage of the driving transistors.
Implementation Method 1
a current detection unit configured to sense a global current supplied to or emitted from the display panel
Data Source
AI summary
Provided are a display device and a method of operating the same. The method of operating the display device, which includes a display panel including a plurality of pixels and a data driver configured to provide data signals having different voltage levels to all data lines connected to pixels, comprises steps of applying a data signal having a first data voltage to all the data lines, determining whether a preset sensing current flows in a target wire, and applying a data signal having a second data voltage to all the data lines, wherein the second data voltage is offset from the first data voltage by a certain voltage level.