OLED Display Driving Transistor Compensation for Luminance Dispersion
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Solution Overview
Problem
The organic light emitting display device faces reliability and lifetime issues due to dispersion in characteristic values of driving transistors, which affects luminance quality and overall display performance.
Innovation Solution
Incorporating a sensing unit to measure characteristic values of driving transistors and a compensation unit that adjusts a common reference voltage applied to all pixels, effectively compensating for dispersion shifts and maintaining consistent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a driving transistor is used to drive the OLED in each pixel, then the display device achieves fast response rate and high light emitting efficiency, but the characteristic value dispersion of driving transistors degrades reliability and lifetime
Solution Approach 1:
The patent applies preliminary action by sensing the characteristic values of driving transistors before they cause significant degradation, and by proactively adjusting the reference voltage to compensate for predicted dispersion shifts. The sensing unit measures threshold voltages and mobility values in advance, allowing the system to pre-adjust compensation parameters before luminance quality deteriorates, thus maintaining reliability while preserving the fast response characteristics of OLEDs.
Solution Approach 2:
The patent implements feedback by continuously monitoring the characteristic values of driving transistors through the sensing unit and using this information to dynamically adjust the reference voltage via the compensation unit. This closed-loop feedback mechanism detects dispersion in threshold voltage and mobility, then automatically compensates by modifying the reference voltage applied to all pixels, thereby maintaining driving transistor reliability without sacrificing the high productivity of OLEDs.
2Duration of action of stationary object
If the characteristic value of driving transistor changes with time, then the display device operates continuously, but luminance quality of the pixel degrades
Solution Approach 1:
The patent uses feedback to continuously monitor the characteristic values of driving transistors over time and dynamically adjust the reference voltage to compensate for temporal changes. The sensing unit measures threshold voltage and mobility at different time points, and the compensation unit modifies the reference voltage based on detected dispersion shifts, thereby maintaining consistent luminance quality throughout the operating duration without degradation.
Solution Approach 2:
The patent applies parameter changes by modifying the reference voltage parameter in response to detected changes in driving transistor characteristics over time. When the sensing unit detects shifts in threshold voltage or mobility distributions, the compensation unit adjusts the reference voltage parameter to counteract these changes, thereby maintaining stable luminance quality throughout the device's operating lifetime despite temporal characteristic variations.
3Adaptability or versatility
If dispersion of characteristic value occurs in driving transistors, then individual pixel characteristics vary, but overall display quality and lifetime are largely degraded
Solution Approach 1:
The patent applies local quality by sensing and compensating for characteristic value dispersion at the individual pixel level rather than treating all pixels uniformly. The sensing unit measures threshold voltage and mobility for each pixel's driving transistor separately, and the compensation unit adjusts the reference voltage based on local dispersion characteristics detected in each pixel, thereby maintaining high display panel reliability despite inherent variations in individual transistor properties.
Data Source
AI summary
The present invention relates to an organic light emitting display device that changes a reference voltage commonly applied to a driving transistor in all pixels, based on a characteristic value sensed according to each pixel.