OLED Display Pixel Stress Reduction via Dynamic Block Segmentation
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Solution Overview
Problem
The degradation of organic light emitting diode (OLED) display pixels due to changes in device characteristics, such as threshold voltage and mobility of driving thin film transistors, leads to reduced image quality and lifespan, especially in long-term displays like interior or public displays where stress deviation between pixels increases.
Innovation Solution
A special operation mode processor divides the display panel into pixel blocks and dynamically determines which pixels to turn on or off based on drive history representative values, adjusting the location and ratio of ON-pixels to reduce stress and stress deviation between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all pixels are driven continuously to display images, then the display function is maintained, but pixel stress and stress deviation increase leading to degradation of image quality and reduced lifespan
Solution Approach 1:
The patent applies periodic action by dividing pixel blocks into multiple groups and alternately driving different groups in different frames. Instead of continuously driving all pixels, the system periodically switches which pixel groups are active, allowing previously driven pixels to rest and recover. This periodic driving pattern reduces cumulative stress on individual pixels while maintaining continuous display functionality through the alternation of different pixel groups.
Solution Approach 2:
The patent segments the pixel array into multiple pixel blocks, with each block containing multiple pixel groups. This segmentation allows independent control and alternating driving of different pixel groups within the same block. By dividing the pixel array into manageable segments, the system can rotate which segments are actively driven, distributing the stress load across all segments over time and preventing any single group from experiencing continuous high stress.
2Reliability
If the same pixel groups are driven continuously, then the display performance is consistent, but stress deviation between pixels increases causing image quality degradation
Solution Approach 1:
The patent implements dynamics by dynamically switching which pixel groups are driven in each frame based on a predetermined pattern. Instead of statically assigning the same pixel groups to be driven continuously, the system dynamically rotates through different pixel groups. This dynamic switching ensures that stress is distributed more evenly across all pixels over time, reducing stress deviation and preventing the degradation of image quality that would result from continuous driving of the same pixel groups.
3Duration of action of stationary object
If pixel driving is optimized to reduce stress, then pixel lifespan is extended, but the complexity of pixel control increases
Solution Approach 1:
The patent applies preliminary action by pre-dividing pixel blocks into multiple pixel groups and establishing a predetermined driving pattern before operation begins. This preliminary organization of pixel groups and their assigned driving sequences simplifies the control logic during actual operation, as the system only needs to follow the pre-established pattern rather than making complex real-time decisions about which pixels to drive. The upfront structuring reduces ongoing control complexity while achieving stress reduction goals.
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 improves image quality and extends the lifespan of OLED displays by reducing pixel stress and stress deviation, allowing for more efficient power consumption and maintaining image quality over time.
Implementation Method 1
electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film
Implementation Method 2
electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film
Data Source
AI summary
A special mode processor drives a display panel to display an image. When the display panel is configured to operate in a special operation mode, the special operation mode processor determines a pixel block size for blocking the plurality of pixels into a plurality of pixel blocks and determines a first set of on-pixels and a first set of off-pixels. The first set of on-pixels is initially turned on and the first set of off-pixels is initially turned off. A drive history representative value is generated for the first group of pixels that represents a drive time and drive characteristic for the first group of pixels. The drive history representative value is compared with a threshold value. Responsive to the drive history representative value exceeding the threshold value, a second set of on-pixels and a second set of off-pixels are turned on and off respectively.