Display Driving Transistor Reset via Periodic Recovery Voltage
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Solution Overview
Problem
Display devices, particularly OLEDs, experience image errors and quality degradation due to brightness non-uniformity caused by deviations in threshold voltage and mobility of driving transistors when the driving frequency changes, especially when using variable refresh rate modes.
Innovation Solution
A display device and method that apply recovery voltages during blank periods, with a timing controller compensating data voltages based on real-time sensing of driving transistor characteristics and determining a reference period for the recovery voltage to reset the transistors, thereby reducing image errors and improving quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable refresh rate mode is used to adapt to different image types, then adaptability is improved, but image errors occur when driving frequency changes
Solution Approach 1:
The patent applies periodic recovery voltages to the driving transistor during blank periods at regular intervals. This periodic action resets the transistor characteristics before they can drift into causing image errors, thereby maintaining image quality stability while the display operates at variable refresh rates adapted to different image types.
Solution Approach 2:
The recovery voltage is applied in advance during the blank period before the next display period begins. This preliminary action prevents threshold voltage drift and mobility degradation from occurring, ensuring that when the next frame is displayed, the driving transistor is already reset and ready to operate correctly at the current refresh rate.
2Productivity
If driving frequency changes are implemented, then productivity is improved, but image errors appear due to transistor characteristic deviations
Solution Approach 1:
The patent implements periodic application of recovery voltages during blank periods at defined intervals. This ensures that regardless of how the refresh rate changes, the driving transistor receives regular resets that prevent characteristic deviations, thereby maintaining image quality consistency across different productivity levels.
Solution Approach 2:
The system monitors the driving frequency changes and adjusts the timing of recovery voltage applications accordingly. By providing feedback on the actual operating conditions, the system ensures that recovery voltages are applied at appropriate intervals to maintain image quality even as productivity requirements change the refresh rate.
3Reliability
If recovery voltage is applied frequently, then image quality is improved, but energy consumption increases
Solution Approach 1:
The recovery voltage is applied periodically during blank periods rather than continuously. This periodic application maintains image quality by resetting transistor characteristics when needed, while consuming minimal energy by utilizing otherwise idle blank period time when no pixels are being driven anyway.
Solution Approach 2:
The recovery voltage application continues seamlessly during blank periods without interrupting the display operation. This maintains continuous image quality improvement while efficiently using time when the display is naturally not updating, thereby avoiding additional energy consumption beyond what is already required for normal operation.
Data Source
AI summary
A display device and a display driving method are disclosed. The display device includes a display panel including gate lines, data lines, and a plurality of subpixels including a plurality of driving transistors, a gate driving circuit configured to apply scan signals to the gate lines, a data driving circuit configured to convert image data into data voltages and apply the data voltages to the data lines, and a timing controller configured to compensate the data voltages applied to the plurality of driving transistors based on a real-time sensing process of characteristic values of the plurality of driving transistors, and control an application of a recovery voltage to at least one driving transistor of the plurality of driving transistors a plurality of times within a blank period of a frame period based on a reference period to reset the at least one driving transistor during the blank period.