Backlight Luminance Control via Zone Gain Adjustment
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in effectively controlling backlight brightness across different zones, leading to inadequate contrast and layering due to uniform backlight brightness and insignificant differences in brightness levels.
Innovation Solution
The method involves determining backlight duty ratios and current values for each zone, calculating average values, and applying gains to adjust backlight current values, allowing for differential control of backlight zones to enhance contrast and layering by using preset gain curves and power adjustment coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform backlight brightness is used across all zones, then device complexity is reduced, but contrast and layering are insufficient
Solution Approach 1:
The backlight is divided into multiple backlight zones (e.g., first backlight zone, second backlight zone) that can be independently controlled. Each zone has its own duty ratio and current value that can be adjusted separately to achieve different brightness levels, thereby improving contrast and layering without requiring complete redesign of the backlight control system
Solution Approach 2:
Different backlight zones are assigned different control parameters (duty ratios, current values) based on local requirements. The first backlight zone may have different brightness characteristics than the second backlight zone, allowing each area to be optimized for its specific display needs while maintaining overall system simplicity
2Illumination intensity
If differential control of backlight zones is implemented, then contrast and layering are improved, but device complexity increases
Solution Approach 1:
The system dynamically adjusts duty ratios and current values for different backlight zones based on real-time image content analysis. The controller modifies control parameters frame-by-frame or block-by-block to optimize brightness distribution, achieving high contrast without requiring complex hardware modifications
Solution Approach 2:
The invention changes control parameters (duty ratio, current value) to achieve differential brightness control. By adjusting these electrical parameters rather than modifying physical structure, the system achieves improved contrast while keeping hardware complexity manageable
3Illumination intensity
If high backlight current values are used to improve brightness, then illumination intensity increases, but power consumption increases
Solution Approach 1:
Instead of uniformly increasing backlight current for the entire display area, the system applies partial action by increasing current only in specific zones where higher brightness is needed. This selective approach achieves improved brightness where required while minimizing overall power consumption
Solution Approach 2:
The system uses periodic PWM modulation to control backlight emission. By switching the backlight on and off at high frequencies with adjusted duty cycles, the system achieves precise brightness control and average power reduction compared to continuous operation at high current
Data Source
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AI summary
Some embodiments of the invention disclose a method and apparatus for controlling backlight brightness, and a display device, and the method for controlling backlight brightness includes: determining a backlight duty ratio of each backlight zone according to a backlight value of each backlight zone; determining a plurality of backlight areas in the current backlight module, and calculating statistically the average backlight value of each backlight area; searching for a gain corresponding to each backlight area according to the average backlight value of the backlight area, and a preset gain curve, and determining a backlight current value of the backlight area to which a gain is applied, according to the gain; and generating a driver signal according to the backlight current value of the backlight area to which the gain is applied, and the backlight duty ratio of each backlight zone in the backlight area to control backlight brightness of each backlight zone in the backlight area, so that there are different backlight current values of the different backlight areas, thus improving more effectively the contrast and the hierarchical sense of an image being displayed.