OLED Driving Method Preventing Image Stains via Sub-frame Segmentation
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Solution Overview
Problem
Organic light emitting display devices using analog driving techniques face challenges in preventing image stains associated with both low and high gray-levels, as existing methods either fail to adequately address these issues or compromise timing margins for display operations.
Innovation Solution
The method involves dividing a frame into a blank frame and multiple sub-frames, determining if a data signal is from a high or low gray-level region, and applying specific setting data signals to the pixel circuits in each sub-frame to implement the desired gray-level using an average value of sub-frame gray-levels, thereby preventing image stains and securing sufficient timing for display operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog driving technique is used to control current through OLED, then gray-level display is achieved, but image stains occur at both low and high gray-levels
Solution Approach 1:
The patent divides the frame into multiple sub-frames and segments the gray-level display into different time periods. By applying different driving voltages to different sub-frames and calculating the average luminance, the patent achieves accurate gray-level display while preventing image stains through temporal segmentation of the display process
Solution Approach 2:
The patent employs periodic switching of driving voltages across multiple sub-frames. By periodically alternating between different voltage levels and calculating the time-averaged luminance, the patent achieves both image stain prevention and accurate gray-level representation through periodic modulation of the driving signal
2Object-affected harmful factors
If digital driving technique is used to prevent image stains, then image quality improves, but timing margin for display operations is reduced
Solution Approach 1:
The patent dynamically adjusts the driving voltage based on the gray-level requirements of different sub-frames. By using analog voltage control that adapts to different display needs within each frame cycle, the patent maintains sufficient timing margins while preventing image stains through dynamic voltage modulation rather than fixed digital switching
3Object-affected harmful factors
If average value of sub-frame gray-levels is used to implement gray-level, then image stain is prevented, but device complexity increases
Solution Approach 1:
The patent performs preliminary calculations of the required driving voltages for each sub-frame based on the target gray-level and the desired average luminance. By pre-calculating and storing the voltage values needed for each sub-frame, the patent simplifies the real-time control complexity while achieving image stain prevention through planned voltage sequences
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 effectively prevents image stains at both low and high gray-levels while maintaining a sufficient timing margin for high-quality, high-resolution image display in organic light emitting display devices operating on analog driving techniques.
Implementation Method 1
an organic light emitting display device includes a display panel including a plurality of pixel circuits... an organic light emitting diode of each pixel circuit
Data Source
AI summary
A method of driving an organic light emitting display device includes: dividing one frame into one blank frame and sub-frames; determining whether a data signal to be applied to a pixel circuit of the organic light emitting display device is a data signal of a high gray-level region or a data signal of a low gray-level region based on a predetermined reference gray-level; applying the data signal to the pixel circuit in all of the sub-frames when the data signal is the data signal of the high gray-level region; and applying a first setting data signal corresponding to a gray-level higher than the reference gray-level to the pixel circuit in some of the sub-frames, and applying a second setting data signal corresponding to a zeroth gray-level to the pixel circuit in other sub-frames among the sub-frames when the data signal is the data signal of the low gray-level region.