Region-Backlit LCD Power Reduction via Histogram Luminance Control
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Solution Overview
Problem
Conventional liquid crystal display devices with backlight systems face high power consumption due to constant lighting requirements, and existing region-divided LED backlight configurations suffer from manufacturing accuracy issues, color variation, and temperature-dependent performance, leading to suboptimal image quality and increased power usage.
Innovation Solution
A liquid crystal display device with a backlight system divided into regions, utilizing a histogram detector to analyze image signal gradation distribution, an image gain calculator to adjust light emission based on maximum luminance and gain calculations, and a light emission luminance calculator to optimize luminance across each region, ensuring efficient power use and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the backlight device is divided into multiple regions with independent control, then power consumption is reduced by controlling light emission according to image brightness, but manufacturing accuracy issues cause brightness and color variations among regions
Solution Approach 1:
The patent applies local quality by dividing the backlight device into multiple regions and controlling the light emission luminance of each region independently based on the brightness distribution of the image signal. The luminance control unit adjusts each region's output according to local image characteristics, allowing differentiated control strategies for different areas. This resolves the contradiction by enabling power savings in dark regions while maintaining manufacturing tolerances through localized adjustment rather than requiring perfect uniformity across all regions.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the light emission luminance parameter of each backlight region based on the histogram analysis of image brightness distribution. The system changes the operating parameters of the backlight in response to varying image content, transitioning between different luminance states to optimize both power consumption and visual quality, thereby resolving the trade-off between energy efficiency and manufacturing precision limitations.
2Use of energy by moving object
If LED light sources are used with region-divided control, then power consumption is reduced, but temperature dependence causes brightness reduction and wavelength changes in R LEDs
Solution Approach 1:
The patent implements feedback mechanisms through histogram detection of the image signal brightness distribution, which informs the luminance control unit's adjustments to each backlight region. This feedback loop allows the system to compensate for temperature-induced variations by adapting the luminance output based on actual image content requirements, thereby maintaining reliable display performance while consuming less power. The feedback enables dynamic compensation for R LED wavelength and brightness changes.
3Use of energy by moving object
If complete region separation is implemented, then power consumption is minimized, but it becomes difficult to determine locations of adjacent regions due to low manufacturing accuracy
Solution Approach 1:
The patent applies partial action by implementing region division and independent control without requiring complete physical separation or perfectly sharp boundaries between regions. The system accepts partial overlap and gradual transitions at region boundaries, controlling luminance based on histogram analysis rather than demanding precise boundary detection. This approach minimizes power consumption through regional control while avoiding the difficulties of exact boundary localization due to manufacturing tolerances.
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
The solution reduces power consumption while maintaining high image quality by dynamically controlling light emission across regions, mitigating the effects of temperature and manufacturing inaccuracies, and enhancing the uniformity of brightness and color.
Implementation Method 1
a backlight device disposed on the back side of the liquid crystal panel, and divided into a plurality of regions, the backlight device comprising light sources in each of the regions
Data Source
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AI summary
A liquid crystal panel displays an image from image signals. A backlight device is disposed on the back side of the liquid crystal panel, and is divided into a plurality of regions. The backlight device comprises light sources in each of the regions. The light sources are positioned to emit light onto the liquid crystal panel. A histogram detector detects an image signal gradation distribution for each region and to produce a histogram therefrom. An image gain calculator calculates a gain from the detected gradation distribution of the histogram detector, and controls light emission from each light source in each region of the backlight device. A light emission luminance calculator controls the light emission luminance of each light source based on a maximum luminance of the light sources and based on an inverse number of the gain calculated in the image gain calculator.