LCD Power Conservation via Pixelated Filter Luminance Control
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Solution Overview
Problem
Current power conservation techniques for LCD displays often result in noticeable changes to video output when reducing backlight luminance, leading to increased power consumption as users reactivate the display to maintain visibility, as these techniques abruptly alter the entire image or assume drastic backlight reductions.
Innovation Solution
The method involves gradually altering video information by reducing luminance and transmissivity through pixelated filters while maintaining the current backlight level, allowing the backlight to be lowered to a lower luminance level without significantly affecting perceived aggregate luminance, thereby reducing power consumption without drawing attention to the change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the backlight luminance is reduced to conserve power, then power consumption decreases, but the video output becomes noticeably dimmer and harder to see
Solution Approach 1:
The system performs preliminary action by gradually darkening the displayed image content before reducing backlight luminance. This prepares the user's visual perception so that when the backlight dimming occurs, the contrast change is minimal and the video output remains perceptible. The image darkening is applied in advance to compensate for the upcoming backlight reduction.
Solution Approach 2:
The system changes parameters by simultaneously adjusting both the image content luminance and the backlight luminance. By modifying the image parameters (darkening) in coordination with backlight parameter changes, the system achieves power conservation while maintaining acceptable video output visibility. The coordinated parameter changes ensure that the ratio between image brightness and backlight brightness remains relatively constant.
2Use of energy by moving object
If the backlight luminance is drastically reduced to save power, then power consumption decreases significantly, but the sudden change draws user attention and causes them to reactivate the display
Solution Approach 1:
The system applies preliminary action by progressively darkening the image content over time before the backlight reduction. This gradual preparation desensitizes the user to luminance changes, so when the backlight is eventually reduced, the change is not perceived as sudden or drastic. The preliminary image darkening masks the backlight transition, preventing user reaction.
Solution Approach 2:
The system employs dynamics by implementing a gradual, time-based transition rather than an abrupt change. The image darkening occurs progressively over multiple frames or seconds, and the backlight reduction is timed to coincide with this gradual adaptation. This dynamic approach makes the transition imperceptible to users, maintaining ease of operation.
3Use of energy by moving object
If the entire LCD image is uniformly altered to reduce luminance, then power consumption decreases, but the video output quality deteriorates and becomes noticeably degraded
Solution Approach 1:
The system changes parameters by coordinating image luminance reduction with backlight luminance reduction. By adjusting both parameters together, the system maintains the relative contrast relationships within the image while achieving overall power savings. This coordinated parameter change preserves video output quality better than uniform image alteration alone.
Solution Approach 2:
The backlight acts as an intermediary that mediates between the image content and the user's perception. By adjusting the backlight luminance in coordination with image luminance, the system uses the backlight as a mediating element to maintain overall visibility and quality. The backlight compensates for image darkening, ensuring that video output quality remains acceptable while still achieving power conservation.
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 conserves power by minimizing perceptible changes to the user, allowing the LCD to operate at lower backlight luminance levels for extended periods, thereby reducing overall power consumption and extending battery life in portable devices.
Implementation Method 1
The alteration includes reducing luminance and transmissivity of the video information using pixilated filters included in the LCD
Data Source
AI summary
Described herein are power conservation systems and methods that reduce power consumption for an electronics device including a liquid crystal display (LCD). The LCD includes a backlight that offers multiple luminance levels, where each level consumes a different amount of power. The systems and methods alter video information while the backlight remains at a backlight luminance level. The alteration reduces luminance for the video information to produce new video information that can be presented at a lower backlight luminance level. Change to the lower backlight luminance level may then occur without significantly affecting aggregate luminance of the new video information, as perceived by a user. The LCD and electronics device consume less power at the lower luminance level.