Backlight Control for LCDs Using Spatial Filtering to Reduce Power
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Solution Overview
Problem
Liquid crystal display devices with constant backlight brightness suffer from light leakage during full-off states, leading to poor display effects and high power consumption due to nonzero light transmittance, especially in dark image content.
Innovation Solution
An apparatus and method for backlight control that calculates initial brightness values for each backlight block, performs spatial and temporal filtering to adjust these values, and generates a brightness control signal to adjust the backlight source, ensuring intermediate brightness values are greater than or equal to initial values, thereby reducing power consumption and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If constant brightness backlight is used, then display panel can provide sufficient light source, but power consumption increases and light leakage occurs in dark content
Solution Approach 1:
The backlight source is divided into multiple independently controllable backlight blocks, allowing each block to be adjusted according to the local brightness requirements of different image regions, rather than using a single constant brightness backlight for the entire display area
Solution Approach 2:
Different regions of the backlight source are assigned different brightness levels based on the local content requirements, with darker regions receiving lower brightness and brighter regions receiving higher brightness, achieving localized brightness optimization
2Use of energy by moving object
If backlight brightness is reduced for power saving, then power consumption decreases, but display uniformity deteriorates due to uneven brightness distribution
Solution Approach 1:
The system calculates initial brightness values for each backlight block based on the input image data, then performs spatial filtering where each block's brightness is adjusted based on feedback from its neighboring blocks, ensuring smooth transitions and maintaining overall brightness uniformity
Solution Approach 2:
Spatial filtering is performed in advance to determine the final brightness values for each backlight block, preventing potential brightness unevenness before it occurs by pre-adjusting the brightness distribution across different blocks
Data Source
AI summary
Disclosed is a method and an apparatus for backlight control and a display device. The apparatus comprises: a block brightness module for calculating an initial brightness value of each backlight block in a backlight source according to initial image data; a filtering module for performing spatial filtering and temporal filtering on the initial brightness value of each backlight block to obtain an adjusted brightness value of each backlight block; a control module for generating a brightness control signal according to the adjusted brightness value of each backlight block to adjust brightness of the backlight source. An intermediate brightness value of each backlight block is no less than the initial brightness value of that backlight block. Based on backlight adjustment for reducing power consumption, display effect reduction on a portion of image due to uneven brightness of the portion of the image during the spatial filtering is avoided.