Display Pixel Group Switching to Prevent Image Sticking
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Solution Overview
Problem
Image sticking occurs on LCD and plasma displays due to the accumulation of ionic impurities, causing persistent images that are difficult to remove, especially in applications where static images are displayed for extended periods.
Innovation Solution
Pixels are grouped and selectively de-energized in a controlled manner to mitigate the accumulation of ionic impurities, using a pixel selector to iteratively turn off and on subsets of pixels, thereby reducing the reversed voltage that causes image sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixels are continuously energized to maintain display brightness, then display brightness is maintained, but ionic impurities accumulate and cause image sticking
Solution Approach 1:
The display is divided into multiple pixel groups, and the patent applies different energy states to different groups. While one group is de-energized to prevent impurity accumulation, another group remains energized to maintain display brightness. This segmentation allows the system to simultaneously prevent image sticking and maintain visibility.
Solution Approach 2:
The patent implements periodic switching between different pixel groups. Over time, all pixel groups are cycled through de-energized and energized states. This periodic action ensures that ionic impurities are periodically reset while maintaining continuous display functionality through strategic group switching.
2Object-affected harmful factors
If all pixels are de-energized to prevent image sticking, then image sticking is prevented, but display brightness is lost
Solution Approach 1:
Instead of de-energizing all pixels simultaneously, the patent segments the pixel array into multiple groups and de-energizes only one group at a time. This allows the remaining groups to maintain their energized state and continue displaying images, thus preventing complete loss of display brightness while still achieving image sticking prevention through the de-energized group.
Solution Approach 2:
The patent applies partial de-energization rather than complete de-energization. By selectively de-energizing only a portion of the pixel array (one group out of multiple groups), the system achieves sufficient image sticking prevention without the excessive action of shutting down the entire display, thereby maintaining adequate brightness.
3Object-affected harmful factors
If image sticking prevention is implemented through pixel de-energization, then image sticking is reduced, but power consumption increases due to controlled switching
Solution Approach 1:
The patent uses periodic switching between energized and de-energized states for pixel groups. This periodic action prevents ionic impurity accumulation by regularly resetting the voltage fields. The controlled periodic switching manages power consumption by keeping pixels in the lowest energy state (de-energized) during prevention cycles while maintaining brightness during display cycles.
Solution Approach 2:
The patent dynamically adjusts the energy state of different pixel groups based on operational needs. The system transitions between static (de-energized) and active (energized) states flexibly, allowing optimization of power consumption while maintaining image sticking prevention. This dynamic control enables the system to adapt power usage to actual display requirements.
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 method effectively prevents image sticking while conserving power and maintaining display brightness, especially in applications like point of sale devices and other displays with static content, by addressing the root cause of ionic impurity buildup.
Implementation Method 1
The cause of LCD image sticking is due to an accumulation of ionic impurities inside the liquid crystal materials. When slight DC voltage occurs, the charged impurities build up a reversed voltage field.
Implementation Method 2
When slight DC voltage occurs, the charged impurities build up a reversed voltage field. When the power is removed, the reversed voltage makes the LCD molecules twist differently from the other parts of the LCD
Data Source
AI summary
Embodiments herein describe techniques for mitigating or preventing image sticking in a display screen (e.g., a LCD or plasma display). In one embodiment, the pixels in the display screen are assigned to different groups. During a first time period, the display turns off a subset of the pixels in each of the groups. De-energizing the pixel mitigates or removes the reversed voltage that creates image sticking. During another time period, another subset of pixels in each of the groups is de-energized while the pixels that were de-energized in the previous time period are energized.