AMOLED Sub-Pixel Write-Back Voltage Compensation for Afterimage Elimination
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Solution Overview
Problem
In Active-Matrix Organic Light-Emitting Displays (AMOLEDs), threshold voltage drift in thin film transistors under long-time pressurization and high-temperature conditions leads to afterimage phenomena due to differences in drive thin film transistors, which current compensation methods fail to adequately address, causing display brightness inconsistencies.
Innovation Solution
A compensation method and apparatus that determine a write-back voltage for each sub-pixel based on a data voltage and a gain value greater than 1, allowing for voltage compensation during the blank period of the current frame, utilizing a sense line to detect electrical signals and calculate compensation voltages for subsequent frames, thereby eliminating afterimage effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sense line is connected between the drive thin film transistor and OLED device to detect electrical signals, then compensation can be performed, but the OLED device darkens and a dark line appears in the row of pixels
Solution Approach 1:
The patent applies preliminary action by writing back the compensation voltage to the pixel in advance during the blank period before the actual display period. This ensures that when the sense line is activated for detection, the pixel has already been compensated, preventing the dark line from being visible to human eyes while maintaining measurement capability.
2Loss of information
If the sense thin film transistor is turned on during scan time of the blank period to detect electrical signals, then compensation voltage can be determined, but current flows to the sense line causing the OLED device to darken
Solution Approach 1:
The patent converts the harmful effect of the sense transistor activation (which causes darkening) into a beneficial process by performing the voltage write-back operation during the same period. The darkening that would normally be harmful is transformed into an opportunity to apply compensation before display, making the harm invisible to human perception.
3Reliability
If compensation is performed during the blank period by writing back voltage to pixels, then afterimage effects can be eliminated, but the process complexity increases
Solution Approach 1:
The patent implements feedback by detecting the electrical signal of the drive thin film transistor, determining the compensation voltage based on the detected signal, and writing back the compensation voltage to the pixel. This closed-loop feedback mechanism eliminates afterimage effects and ensures display consistency while managing process complexity through systematic implementation.
Data Source
AI summary
A compensation method and a compensation apparatus for an organic light-emitting display, and a display device are disclosed. The compensation method includes: determining a write-back voltage of each sub-pixel to be compensated in a row to be compensated in a current frame according to a data voltage and a gain value of the sub-pixel to be compensated in the row to be compensated in the current frame, the gain value being greater than 1; and respectively writing back the write-back voltage of each sub-pixel to be compensated in the row to be compensated in the current frame correspondingly to the sub-pixel to be compensated in the row to be compensated in scan time of a blank period of the current frame.