Backlight Modulation for External Displays to Save Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
External displays consume significant power due to constant backlight operation, and existing power-saving methods either compromise image quality or increase complexity and cost by modifying backlight brightness without considering user or system preferences.
Innovation Solution
Implementing a display power savings functionality within the computing device that adjusts backlight brightness and pixel modifications based on image statistics and user policies, using techniques like pulse width modulation (PWM) and voltage level control, to maintain image quality while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the backlight is turned off during image refresh, then power consumption is reduced, but motion artifacts occur and image quality deteriorates
Solution Approach 1:
The patent applies periodic action by pulsing the backlight on and off during the refresh cycle. The backlight is turned off during active image writing periods and turned on during vertical blanking intervals, creating a periodic pattern that reduces power consumption while avoiding motion artifacts. This is achieved by synchronizing backlight pulses with the display refresh timing, ensuring the backlight is only off when no image data is being written to the panel.
Solution Approach 2:
The patent implements dynamic backlight control by adjusting the backlight brightness and timing based on the actual refresh cycle requirements. The system dynamically modifies backlight operation parameters (on/off timing, duration) to match the specific needs of each refresh cycle, optimizing both power savings and image quality based on real-time display conditions.
2Use of energy by stationary object
If the backlight brightness is reduced to save power, then energy consumption decreases, but image quality and visibility are compromised
Solution Approach 1:
Instead of continuously reducing backlight brightness, the patent uses periodic on/off action during the refresh cycle. The backlight operates at full brightness during vertical blanking intervals when no image writing occurs, and is completely off during active refresh periods. This periodic full-brightness operation maintains image quality when needed while achieving power savings through the off periods.
3Reliability
If the backlight is constantly on, then image quality is maintained, but power consumption increases significantly
Solution Approach 1:
The patent resolves this contradiction by implementing periodic backlight operation synchronized with the display refresh cycle. The backlight is turned off during active image writing periods when constant illumination would be unnecessary, and turned on during vertical blanking intervals when the display is stable. This periodic action maintains image quality during visible periods while eliminating wasteful power consumption during non-visible periods.
Solution Approach 2:
The system uses feedback from the display refresh timing signals to control backlight operation. The backlight driver receives timing information about when image writing occurs and adjusts backlight state accordingly, creating a feedback loop that optimizes power consumption based on actual display needs while maintaining image quality.
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 reduces power consumption by dynamically adjusting backlight brightness and pixel enhancements, maintaining image quality and user preferences, thereby enhancing energy efficiency without increasing complexity or cost.
Implementation Method 1
using techniques like pulse width modulation (PWM) and voltage level control
Implementation Method 2
The backlight illuminates the optical stack so that the images written thereon can be seen by the user
Data Source
AI summary
In general, in one aspect, an apparatus receives pixels associated with an image destined for an external display and determines a reduced backlight brightness for the external display and corresponding changes to the pixels to approximate overall quality of the image with current backlight brightness. Backlight commands are generated for the reduced backlight brightness and the pixels are enhanced to correspond to the reduced backlight brightness. The enhanced pixels and the backlight commands are transmitted to the external display via a display interface that supports backlight control. The display interface may be a wireless interface or a wired (cabled) interface (e.g., display port (DP), high definition multimedia interface (HDMI), video graphics array (VGA)). The functionality of the apparatus is included in a computing device so that backlight brightness reductions and corresponding pixel changes can be made taking into account policies of the computing device and user preferences.