OLED Data Driver Kick-Back Compensation via Successive Voltage Application
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Solution Overview
Problem
Organic light emitting displays experience image quality degradation due to the kick-back phenomenon, which occurs when parasitic capacitance causes fluctuations in gate and sensing voltages, leading to errors in threshold voltage and mobility sensing, resulting in inaccurate compensation and degraded image quality.
Innovation Solution
An organic light emitting display that successively supplies a high driving voltage higher than the sensing data voltage to the data line during the sensing mode, ensuring a consistent kick-back voltage across all pixels, thereby minimizing errors in sensing values and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same data voltage is applied to each pixel, then manufacturing simplicity is maintained, but luminance variation occurs due to deterioration of the light emitting element, change of channel mobility, and threshold voltage variation
Solution Approach 1:
The patent changes the data voltage parameter dynamically: during frame periods, the same data voltage is applied to all pixels for simplicity, but during blanking periods, different sensing voltages are applied to different pixels to compensate for individual variations in threshold voltage and channel mobility, thereby maintaining luminance uniformity
2Measurement precision
If external compensation sensing is performed in blanking period, then real-time compensation is achieved, but kick-back phenomenon causes voltage fluctuations leading to sensing errors
Solution Approach 1:
The patent applies a preliminary high driving voltage to the data line before performing sensing operations during the blanking period. This preliminary action ensures that the data line is fully charged and stable, preventing kick-back voltage fluctuations during subsequent sensing operations and ensuring accurate measurement of pixel characteristics
3Measurement precision
If sensing voltage is applied to data line during blanking period, then pixel characteristics are sensed, but kick-back voltage varies according to frame period data voltage level causing compensation errors
Solution Approach 1:
The patent applies a high driving voltage to the data line before sensing operations during the blanking period. This preliminary charging action ensures that regardless of the data voltage level during the frame period, the data line is reset to a known high voltage state, eliminating variations in kick-back voltage and ensuring consistent sensing accuracy for threshold voltage and mobility measurements
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
This approach prevents image quality degradation by ensuring all pixels experience the same kick-back voltage, leading to uniform sensing values and improved image fidelity.
Implementation Method 1
a kick-back phenomenon in which a gate voltage and a sensing voltage fluctuate due to parasitic capacitance between a data line and each of a scan line and a sensing line
Data Source
AI summary
An organic light emitting display includes a data driver supplying a sensing data voltage in a sensing mode to prevent degradation of image quality occurring due to a kick-back phenomenon. Each pixel of a display panel of the organic light emitting display has its driving characteristic sensed in the sensing mode. The data driver is configured to supply a high driving voltage, which is higher than the supplied sensing data voltage, and both voltages are successively applied to a data line of the display panel in the sensing mode.