2D LED Backlight Control for Flicker and Burn-In Reduction
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Solution Overview
Problem
Electronic displays with two-dimensional backlights face issues such as sharp brightness changes causing artifacts, uneven power consumption leading to voltage drops, asynchronous updates resulting in flickering, and uneven aging leading to 'burn-in' effects.
Innovation Solution
Implement systems and methods that slope brightness changes, limit power consumption, synchronize backlight updates with LCD panel refreshes, and compensate for LED aging and temperature to maintain consistent operation and improve display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If sharp brightness changes are applied to LEDs based on image content, then display responsiveness is improved, but display artifacts occur
Solution Approach 1:
The patent applies periodic action by implementing a slope control mechanism that gradually transitions LED brightness from current to target levels over multiple frames. This periodic adjustment prevents sudden brightness changes while maintaining responsiveness to image content requirements, thereby eliminating display artifacts caused by sharp transitions.
2Reliability
If high voltage is supplied to all LEDs to ensure operation, then LED reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies local quality by determining individual threshold voltages for different LED groups based on their specific operational requirements and image content needs. Instead of uniformly supplying high voltage to all LEDs, the system adjusts voltage levels locally for each LED group, ensuring reliable operation where needed while minimizing power consumption in other areas.
Solution Approach 2:
The patent implements dynamics by making the voltage supply to LEDs adaptive and variable rather than static. The threshold voltage for each LED group is dynamically determined based on current brightness levels, image content requirements, and operational conditions, allowing the system to maintain LED reliability while optimizing power consumption according to real-time needs.
3Speed
If 2D backlight updates independently, then backlight responsiveness is improved, but image artifacts such as flickering occur
Solution Approach 1:
The patent applies merging by synchronizing the backlight update process with the LCD panel refresh process. The slope control mechanism coordinates LED brightness transitions to occur in sync with pixel updates, combining the timing of backlight and panel operations. This synchronization eliminates image artifacts such as flickering and shimmering that occur when the backlight updates independently of the panel.
4Illumination intensity
If multiple LED light sources are used in 2D backlight, then display brightness control is improved, but uneven aging leading to burn-in effects occurs
Solution Approach 1:
The patent applies feedback by implementing a compensation mechanism that monitors and adjusts for variations in LED aging across different light sources. The system tracks the operational history and brightness output of each LED group, using this feedback information to equalize their performance over time. This compensates for uneven aging effects and prevents burn-in artifacts, maintaining uniform display quality despite the use of multiple LED sources.
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
Prevents artifacts, reduces power consumption, minimizes flickering, and avoids 'burn-in' effects by synchronizing backlight updates and compensating for LED aging and temperature, resulting in improved display performance.
Implementation Method 1
The light may be provided by a backlight made up of, for example one or more light-emitting diodes (LEDs)
Data Source
AI summary
An electronic display device has a panel that operates in conjunction with a light-emitting diode (LED) backlight. The device “slopes” or gradually ramps a change in brightness of an LED based on a target brightness value of the LED, a current brightness value of the LED, and temperature at the LED. The device also may limit power to the backlight based on an estimated power consumption of a current row of LEDs of the backlight and power consumption of the other rows of LEDs. The device also may determine a reduced voltage to supply to an LED based on a current to supply to the LED to cause the LED to operate. The device also may send an interrupt to the backlight to block updates to the backlight while image content is written to pixels of the panel. The device further compensates for aging of and temperature at an LED.